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Grass pollen allergens are shown to remain associated with protein material and a yellow pigment during paper chromatography and during dialyses and ultrafiltrations of various types. Dialysable* allergens comprise only a fraction of I per cent of the total activity and the amount of activity extractable by diethylene glycol (DEG) and similar solvents is of the same order. Besides the allergens, the DEG and aqueous extracts contain large amounts of inositol, glucose and fructose, also some yellow pigments and phosphates. Larger amounts of free and combined amino acids are found in the aqueous than in the DEG extracts, but the reverse is true for sucrose. In addition the DEG extracts contain a yellow glucoside different from the dactylen of the aqueous extracts, a glucosan and an arabinose-galactose-pigment complex, only the latter being associated with any activity. The spontaneous release of the crystalline dactylen from originally clear aqueous pollen extracts is found not to be caused by enzymes. The washed crystals are found to be chromatographically and electrophoretically homogeneous and devoid of allergenic activity. [ABSTRACT FROM AUTHOR]

Lists articles to be published in the 'Immunology' periodical. Role of antigen presenting cells and interleukin-12 in the priming of antigen specific CD4[sup +] cells by immune stimulating complexes; Cell activation by monosaccharide lipid A analogs utilizing Toll-like receptor 4; Cytokine synthesis.

The experiments reported in this paper examine the cell-surface phenotype (CD5, CD4, CD8, TI9, MHC class II and sIg) and cell output of lymphocyte subsets circulating through a subcutaneous lymph node in the sheep fetus, in an environment unaffected by foreign antigen and circulating immunoglobulins. CD4+ lymphocytes were the major T-cell subset in fetal lymph and were clearly enriched in lymph compared with blood, whereas TI9+, CD8+ and B lymphocytes were not. It seems likely that in the fetus CD4+ lymphocytes are extracted from the blood at a faster rate than are other T-cell subsets and B cells. There was a much higher percentage of CD8+ and T null cells and a lower percentage of MHC class II+ and B cells circulating in the fetal lymph than in adult lymph, while the percentage of TI9+ lymphocytes in fetal blood was twice that in the adult. Although the hourly cell output from an adult prescapular lymph node was far higher than that from a fetal lymph node, the circulation of lymphocytes through fetal lymph nodes was much greater per gram lymph node weight than that through adult lymph nodes. The wholesale recirculation in the fetus of all the major T-cell subsets found in the adult is paradoxical because it is not known what function they serve in the fetus in the absence of antigen and ongoing immune responses, although clearly they are not memory cells. [ABSTRACT FROM AUTHOR]

As perhaps the staunchest advocates of repertoire purging as the central mechanism of immunological tolerance, we note with satisfaction a spate of recent, elegant papers which suggest an intrathymic clonal abortion model as the explanation for at least some examples of T-cell tolerance. This view agrees with the classical formulation of the Billingham-Brent-Medawar school of tolerance as a specific, central failure of immune responsiveness. Repertoire purging within the B-lymphocyte compartment remains much more controversial. There is no doubt that experimental models exist where the B cell is the reversible target of tolerance induction. The question is, in view of the ease of inducing autoantibody formation both in vivo and in vitro, just how relevant are such clonal anergy mechanisms to authentic self-tolerance? Arguments are presented that there must be two windows of tolerance susceptibility in the ontogeny of the B cell; one while it is maturing in the bone marrow, to prevent autoreactivity of high affinity to important accessible self-antigens; and a second soon after activation of pre-memory cells by exogenous antigen, to prevent fortuitous mutations towards high-affinity anti-self-reactivity establishing a forbidden clone. [ABSTRACT FROM AUTHOR]

This paper investigates desensitization in vitro, e.g. the inhibition of the transfer of contact sensitivity to picryl chloride by incubation of the passive transfer population with picrylated spleen cells. It asks whether desensitization is based on the same T-suppressor circuit which is responsible for the inhibition of passive transfer by antigen-specific T-suppressor factor (TsF). In this circuit, the T-suppressor cell which acts at the efferent stage (Ts-eff) makes TsF. This TsF depresses contact sensitivity indirectly by arming a T-acceptor cell (Tacc). The armed Tacc, when exposed to antigen (picrylated spleen cells), liberates a non-specific inhibitor which blocks the transfer of contact sensitivity. The three elements of this T-suppressor circuit occur in nylon wool-purified T cells prepared from the lymph nodes and spleens of mice four days after immunization with picryl chloride. This population transfers contact sensitivity and can be desensitized in vitro. It contains Ts-eff which can be isolated by panning (adherence) on picrylated albumin and detected by their ability to inhibit passive transfer. The 24 hr supernatant of cultures of these cells contains TsF. Finally the population contains Tacc which appear in the spleen 2 days after immunization and virtually disappear by 10 days. Further experiments demonstrated that the Ts-eff and the Tacc were not merely present but actually required for desensitization in vitro. Immune cells depleted of both Ts-eff (by panning on picrylated albumin) and Tacc (by arming with anti-oxazolone TsF and panning on oxazolonated albumin) cannot be desensitized. To restore desensitization both Ts-eff and Tacc must be added back. The Ts-eff were characterized as cyclophosphamide resistant, adult thymectomy sensitive cells (Cyr, ATx5), which adhered to antigen and were produced only by specific immunization. The Tacc were characterized as CF5, ATx5 cells which adhered to antigen only after arming with antigen-specific T-suppressor factor and were produced after immunization with an unrelated contact sensitizer, 'oxazolone'. It was concluded that desensitization in vitro was due to the interaction of two distinct T cells: the T-suppressor cell which acts at the efferent stage of the contact sensitivity reaction and the T-acceptor cell which becomes armed with the specific T-suppressor factor produced by the Ts-eff. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to investigate whether an antibody directed against the exocrine secretion, saliva, is able to induce a modification in vivo within the specific cells of the submaxillary glands which synthesize this secretion. The salivary antigens synthesized within the glandular acinar cells are secreted into they respective lumen and are not present in the general circulation or in the intercellular spaces of the gland. When heterologous anti-saliva antibodies are injected into mice, they induce marked lesions within the acinar cells of the submaxillary glands. When different antibodies recognizing different salivary components are injected, they ail induce similar modifications; it is not yet possible to distinguish whether different cells are involved in the synthesis of the different salivary components. The lesions described seem specific since other organs studied, such as the pancreas and the stomach, are unaffected. The different possible mechanisms of this cytotoxic effect are discussed. [ABSTRACT FROM AUTHOR]

The studies reported here indicate that tanned red cells coated with a mixture of chromatographically purified ovalbumin and conalbumin give agglutination titres which are directly related to the amount of antibody (as meas- ured by quantitative precipitation) present against either of these antigens in mixed sera. With whole (unabsorbed) mixed sera, these coated cells record the titre of the major antibody present, whether this is anti-ovalbumin or anti-conalbumin. There was no evidence of greater sensitivity to anti-conalbumin. A trace of ovalbumin in a preparation of conalbumin used to coat cells is fully sufficient to enable them to react with any anti-ovalbumin in a serum. Twice recrystallized ovalbumin still contains some conalbumin. Sera raised against it may contain unexpectedly high levels of anti-conalbumin and this could cause confusion in tanned red cell tests. [ABSTRACT FROM AUTHOR]

Although induced immunological tolerance of histocompatibility antigens is generally considered to be specific, cases of concomitant third-party unresponsiveness may occur. The present paper describes one case in point. Antigenic overlap between original and third-party donor, as well as runt disease have been excluded as possible explanations for the observed lack of specificity. It is hypothesized that an innate inability, of the host to respond to the relevant third-party antigen(s), or the ability of certain antigens to induce tolerance of themselves as well as of distinct but related antigens, may be responsible for the phenomenon. [ABSTRACT FROM AUTHOR]

The experiments described in this paper extend the observations of previous work in vitro demonstrating a decrease in the frequency of antigenreactive units specific for horse RBC in spleen cells from mice primed with KLH. It was observed that the addition of lymphoid cells having T-cell function reconstituted the anti-HRBC response to normal values. Significant enhancement of the response beyond the normal values could be evoked using two dissimilar methods, (i) addition of allogeneic thymus cells, and (ii) restimulation in vitro with the priming antigen. The latter type enhancement was elicited by the addition of small doses of KLH to cultures of spleen cells from mice recently primed with KLH, including cultures otherwise demonstrating antigen-induced suppression. The stimulus required to enhance the response to HRBC in these cultures was specific for the priming antigen, KLH. These results are discussed in the light of current theories of 'antigenic competition' and specific heterologous enhancement. [ABSTRACT FROM AUTHOR]

The purpose of this study was to demonstrate the presence of exoantigens in the intestinal washes of mice infected with H. nana, to partially purify the antigen, and to show identity with heterologous antisera to H. nana soluble proteins. This paper describes the increase in specific activity to tapeworm exoantigens with increased purification both with serum obtained from infected mice and heterologous rabbit serum. [ABSTRACT FROM AUTHOR]

Data presented in this paper indicate that by column chromatography using an O acetylated galactan, a considerable degree of purification of specific antibody to O antigen 5 may be achieved. [ABSTRACT FROM AUTHOR]

The thennoinactivation kinetics of IgE were studied in experimental models revealing the antigenic properties and the basophil-sensitizing capacity of these immunoglobulins. A pool of human sera containing anti-Dactylis gloinerata (Dg) IgE was heated from 5 mm up to 4 hr at 56°. The IgE antigenicity was tested by two polyclonal 125I-labelled anti-IgE antibodies; one anti-IgE was specific of the whole Fc∊ region, while the other had a specificity restricted to the D∊2 domain. Radioimmunoassays showed that the D∊2 epitopes were more rapidly altered than the D∊1 epitopes. The capacity of IgE to bind to basophil Fc∊ receptors was assayed by passive sensitization experiments. Basophil sensitivity towards the Dg pollen extract was tested by histamine release experiments in the presence of this allergen. A progressive decrease in cell sensitivity was observed when IgE samples used for cell sensitization were heated for longer than 5 mm. Thermoinactivation kinetics of IgE revealed an unexpected increase in the apparent quantity and biological activity of IgE heated for 5 mm at 56°. This fact could be due to auto-anti-IgE antibodies linked to the unheated IgE and which interfere with the biological activities of lgE and their quantification. [ABSTRACT FROM AUTHOR]

Histamine release by antigen from rat mast cells was strongly inhibited by prolonged anoxia. The inhibition was reversed by oxygen and by glucose. Thioglycollate in low concentration potentiated histamine release and in high concentration inhibited it. The effects of anoxia and thioglycollate are additive: inhibition was produced by a low concentration of thioglycollate combined with a short incubation in nitrogen. This inhibition was reversed by glucose and became a potentiation. The effects of anoxia, glucose and thioglycollate on histamine release by compound 48/80 were quantitatively similar to those on histamine release by antigen. These results are consistent with the view that two opposing mechanisms are at work: a freeing of tissue SH groups which potentiates the anaphylactic mechanism and a disruption of tissue S-S bonds which inhibits it. Oxygen lack may inhibit by a reduction of S-S bonds as well as by an exhaustion of metabolic stores. [ABSTRACT FROM AUTHOR]

The oxygen consumption of isolated rat mast cells has been determined using a micro capillary, respirometer designed by Cunningham and Kirk and modified to permit stirring and addition of reactants. Uptake ranged from 0·5 pl. per cell per minute in 100 per cent O2 to 0·1 pl. per cell per minute in 1 per cent O2. It remained steady for at least 1 hour and was not affected by the presence of glucose. Under a variety of conditions neither histamine release by antigen added to sensitized cells nor by compound 48/80 added to normal cells resulted in any increase in the rate of oxygen uptake. Oxygen does not appear to be a rate limiting factor. [ABSTRACT FROM AUTHOR]

Rabbits made immunologically unresponsive by neonatal administration of HSA, HGG or BSA were given a course of intravenous injections of the respective antigens, adsorbed on alum, after a lapse of 13-27 months since the last administration of antigen. 8/12 responded to HSA, 4/5 to HGG, 9/10 to BSA, as judged by immune elimination of antigen, but this was delayed in onset and slow compared with that in previously untreated rabbits. The antibody formed was small in quantity and usually failed to precipitate with antigen. The sedimentation coefficients of 131I-labelled antigens, in the presence of excess antibody, were measured by ultracentrifugation through a sucrose density gradient. These showed that only small complexes were formed in some of the non-precipitating antisera. In one instance the diffusion coefficient of the complex was also measured, by a technique based on diffusion through agar gel. The calculated molecular weight of the complex, 330,000 indicated the presence of only two combining sites on the antigen. Combination of the anti-HSA sera with an HSA fragment was also measured. Whereas the amount of the fragment bound by ordinary hyperimmune anti-HSA sera was about one-fifth the HSA bound, the amounts bound by the test sera were relatively much less. Some non-precipitating sera failed to bind the fragment, although they bound HSA. These findings indicate that following neonatally induced immunological unresponsiveness the capacity to respond to antigen returns piecemeal in respect of different parts of the antigenic mosaic, and that it may be severely restricted. The theoretical implications are discussed. [ABSTRACT FROM AUTHOR]

The immunological responses of rabbits to HSA, HGG or BSA were tested at various times later in animals which had received the corresponding antigens before or shortly after birth. As judged by the criterion of failure to show immune elimination of antigen, a high proportion of the rabbits remained unresponsive at times when it was calculated that all the originally administered antigen would have been eliminated from the circulation. Furthermore, removal of antigen by passively administered antibody failed to restore the capacity to respond. It is concluded that, in respect of the antigens used, their persistence in the extracellular body fluids is not a prerequisite for maintenance of immunological unresponsiveness.
Further administration of the same antigen to rabbits which had escaped from a state of specific immunological unresponsiveness generally produced a very weak response, and in a few instances resulted in a return to the unresponsive state.
When the cross-reacting antigens HSA and BSA were administered adsorbed on alum to rabbits made unresponsive by neonatal contact with BSA and HSA respectively, and at the same time a further dose of the original antigen was given, antibodies were formed which were specific for the second antigen and did not cross-react with the first. In only 1/9 animals was responsiveness to the first antigen restored. The significance of these results is discussed. [ABSTRACT FROM AUTHOR]

An adaptation of the technique of disk electrophoresis is described. It allows combination of antigen and antibody, as well as the separation of the free antigen from the complex, in a single electrophoretic step. An Iodine-131 labelled human growth hormone : antihuman growth hormone system was used to demonstrate this combination which was expressed as per cent radioactivity bound to immune γ-globulin. Dilution of antiserum gave reproducible titration curves when run at three different temperatures: 10°, 20°, 35°. The curves obtained at 35° showed increased binding. The reduction of bound radioactivity on addition of unlabelled growth hormone to the sample was a linear function of the logarithm of unlabelled growth hormone. The standard curves obtained are suitable for a highly sensitive assay of human growth hormone. [ABSTRACT FROM AUTHOR]

In continuation of the previous work on organ specificity of bovine adrenal, rabbit antisera against human, porcine and equine adrenal were obtained. It was demonstrated that, in addition to ox, man, pig and horse contain adrenal specific antigens that can be associated with organ preparation obtained by extraction at 100° followed by precipitation at a 72 per cent ethanol concentration. The present study allowed identification of two thermostable adrenal-specific antigens, one of them being species-restricted and the other crossing the species line. The former antigen was serologically dissimilar in man, ox, pig and horse. It could be detected only by homologous anti-adrenal sera and was represented by a thicker precipitation line. The latter antigen could be detected by both homologous and heterologous anti-adrenal sera and it was represented by a thinner precipitation line. This antigen was closely related, thought possibly not identical, in man, ox, pig and horse. [ABSTRACT FROM AUTHOR]

A state of immunological paralysis has been induced in adult CBA mice by intrapertioneal injections of small quantities of bovine γ globulin (BGG). The minimum paralyzing dose of BGG has been found to be between 50 and 200 μg. A dose as small as 2 μg, has been found to have a slight paralyzing effect. The time necessary for the induction of paralysis by 50 μg to 2 mg of BGG in CBA mice is 3-4 days. Paralysis is induced by only one component of BGG; this component is incapable of inducing an antibody response unless an injection of adjuvant is made at the same time or slightly before the injection of the antigen. The BGG is centrifuged at an RCF of 20,00-30,000 g to remove particulate matter. Failure to remove the particulate matter leads to sporadic immune responses in groups of mice injected with the protein. Mice given a paralyzing injection of BGG were subsequently challenged by an injection of BGG in Freund's adjuvant. The result of this challenge was tested by an injection of radioactively-labelled antigen and the elimination of this antigen from the circulation of the challenged mice was followed for several days. 'Immune elimination' can easily be distinguished from 'non-immune elimination'. The presence of antibody to the non-paralysing components of BGG in sera from paralysed mice was confirmed using the Ouchterlony gel-diffusion technique. [ABSTRACT FROM AUTHOR]

A ring precipitation has been found when saline is layered on sera from certain patients with abnormal globulins. Positive reactions were found mainly, but not entirely, in the sera from patients with chronic liver disease. The precipitate formed appeared to be a gamma globulin. The phenomenon may be confused with a true precipitin test but does not give false positive results when studied by the agar diffusion or tanned cell techniques. [ABSTRACT FROM AUTHOR]

Dried ceils of Pasteurella multocida type I were extracted with 2.5 per cent aqueous solution of sodium chloride. Acidification of the extract with HCl to pH 3.8 yielded a fraction containing protein with some polysaccharide and lipopolysaccharide. This was removed by centrifugation. Addition of ethanol to the supernatant precipitated a polysaccharide containing fructose, mannose, glucose and glucosamine. This polysaccharide could be further fractionated into products containing varying proportions of glucosamine and fructose. It is produced by both ‘blue’ non-capsulated and ‘fluorescent&lrsquo; capsulated phases of the same strains. From the former it is almost entirely released into the surrounding medium instead of remaining bound to the surface layers of the bacteria. The purified (heterogeneous) polysaccharide fraction is precipitable and fixes complement with homologous sera. When added in repeated amounts to rabbit and cattle sera against whole bacteria until no further precipitate formed it reduced but did not abolish the mouse-protective power of the sera. It did not immunize mice to challenge when injected subcutaneously or intraperitoneally in doses ranging from 2 to 100 μg. [ABSTRACT FROM AUTHOR]

Rabbit spleen cells, which have been treated in vitro with certain rabbit or guinea-pig antisera (e.g. against human serum albumin) and washed, are capable of specifically adsorbing radio-isotope labelled antigen. The antibody responsible for this effect appears to be distinct from the main precipitating anti-body in the serum and the term ‘cytophilic antibody’ has been suggested. The activity of the cytophilic antibody is not destroyed by heating at 56° C. for half an hour. The cytophilic antibody is not adsorbed by red cells. Spleen cells which have been treated with methanol before treatment with antiserum take up less antigen than non-methanol-treated cells tested in the same way. However, the addition of flesh normal spleen cells to the methanol-antibody-treated cells before the addition of antigen increased the uptake of the latter. [ABSTRACT FROM AUTHOR]

The distribution of antigen and antibody in radial double diffusion systems was studied by means of materials labelled with 131I or 14C. These studies showed that, once a precipitate begins to form, the assumption that antigen and antibody obey the laws of free diffusion is invalid. They also showed that, in the systems used, no antigen and very little antibody diffused past the zone of visible precipitation. It was found that accurate estimates of the diffusion constants of antigens could be obtained by allowing antigen and antibody to diffuse from troughs set at right angles and by measuring the angle of the precipitin line. Examples of the use of this method, and a theoretical treatment are given. An alternative method for estimating the size of antigens is to use the ‘molecular sieve’ properties of gelatin gels, which are sharply graded with the concentration of the gel. [ABSTRACT FROM AUTHOR]

The value of sera containing immuno-conglutinin or conglutinin in demonstrating complement-binding by human blood group iso-antibodies was investigated. Provided that a suitable complement was used, positive results were obtained with all human sera which had been shown by other methods to contain complement-binding antibodies. When human red cells were sensitized with human complement-binding blood group antibody and then treated with horse serum as a source of complement, the strongest reactions were obtained with rabbit immuno-conglutinin; the reactions with bovine serum (containing conglutinin) were distinctly weaker, and the reactions with human sera containing immuno-conglutinin were weaker still. When rabbit complement was used instead of horse complement, stronger reactions were obtained, but it was difficult to avoid ‘false positive’ reactions. When human complement was used, good reactions were obtained with rabbit immuno-conglutinin, but the reactions with bovine conglutinin and human immuno-conglutinin were completely negative. [ABSTRACT FROM AUTHOR]

Use of an intra-articular route of injection (a single, hind limb knee joint) and a protein antigen (human serum albumin)in water-in-oil emulsion with added mycobacterial peptidoglycolipid (or Wax D) failed to induce an adjuvant effect upon the resulting immunological response observed three weeks later. Serum antibody levels as measured by the Farr Test (ABC30 μg/ml) and cell-mediated immunity as measured by a quantitative corneal test were consistently lower than those which followed use of a footpad route for the same injection mixture. [ABSTRACT FROM AUTHOR]

Five tissue specific antigens in guinea-pig epidermis were characterized by heat treatment, enzyme digestion, DEAE-cellulose chromatography, (NH4)2SO4 precipitation, ethanol precipitation and gel filtration. These antigens appeared to be proteins although one was fairly resistant to proteinases. Two antigens (Sp2a and Sp2b) were heat-stable and precipitated at high (NH4)2SO4 concentration (3.0 M—saturation): Sp2b was also precipitated at very high ethanol concentration (50-90 per cent). On electrophoresis, Sp2a was shown to have three distinct molecules, while Sp2b showed two. The molecular weight of one component of Sp2a was 71,000 and that of one component of Sp2b was 13,500, as determined by gel filtration. A third antigen behaved electrophoretically and chromatographically like γ-globulin, but was separated from it by (NH4)2SO4 precipitation. The other two antigens did not show any characteristic features and behaved like many other non-specific tissue antigens. [ABSTRACT FROM AUTHOR]

Summary Norovirus (NoV) -derived virus-like particles (VLPs) resemble empty shells of the virus and NoV P-particles contain only protruding domains of the NoV capsid. Both NoV-derived subviral particles show similar functionality and antigenicity in vitro and are considered to be potential vaccine candidates against NoV gastroenteritis. BALB/c mice were immunized with baculovirus-produced GII-4 VLPs or the corresponding Escherichia coli-produced P-particles by the intramuscular or intradermal route and the NoV-specific antibody and T-cell immune responses were compared. Elevated antibody levels were induced with a single VLP immunization, whereas P-particle immunization required a boost. High avidity antibodies were raised only by VLP immunization. VLP immunization resulted in a balanced T helper type 1/type 2 immune response whereas P-particles induced a T helper type 2-biased response. Only VLP immunization primed T cells for interferon-γ production. Most importantly, cross-reactive B and T cells were induced solely by VLP immunization. In addition, VLP antiserum blocked the binding of heterotypic VLPs to human histo-blood group antigen receptor and saliva. The findings in this study are relevant for the development of NoV vaccines. [ABSTRACT FROM AUTHOR]

Since it was previously shown that protein antigens applied epicutaneously in mice induce allergic dermatitis mediated by production of T helper 2 (Th2) cytokines we postulated that this might induce suppression of Th1 immunity. Here we show that epicutaneous immunization of normal mice with a different protein antigen applied on the skin in the form of a patch induces a state of subsequent antigen-non-specific unresponsiveness caused by suppressor T cells (Ts) that inhibit sensitization and elicitation of effector T-cell responses. Suppression is transferablein vivobyαβ-T-cell receptor CD4+ CD8+ double positive lymphocytes harvested from lymphoid organs of skin patched animals and are not major histocompatibility complex-restricted nor antigen specific. Both CD25+ and CD25– CD4+ CD8+ T cells are able to suppress adoptive transfer of Th1 effector cells mediating cutaneous contact sensitivity.In vivotreatment with monoclonal antibodies showed that the cytokines interleukin (IL)-4, IL-10 and transforming growth factor-β (TGF-β) are involved in the induction of the Ts cells. Additionally, using IL-10–/– mice we found that IL-10 is involved in skin induced tolerance. Furtherin vitroexperiments showed that lymph node cells of skin tolerized mice non-specifically suppress[3H]thymidine incorporation by antigen-stimulated immune cells and this effect can be abolished by adding anti-TGF-β, but not anti-IL-4 nor anti-IL-10 antibodies. These studies indicate the crucial role of TGF-β in skin induced tolerance due to non-antigen-specific Ts cells and also show that IL-4, IL-10 and TGF-β play an important role in the induction of epicutaneously induced Ts cell suppression. [ABSTRACT FROM AUTHOR]

Recent studies suggest that neutrophils may play a role in antigen presentation. In support of this hypothesis it has been shown that these cells appear to contain cytoplasmic stores of molecules required for this function, i.e. major histocompatibility complex class II (DR) antigen, CD80 and CD86. In this study we have considered a mechanism for the translocation of these preformed molecules onto the cell surface which does not require active synthesis. Cross-linking of the Mac-1 molecule (CD18 + CD11b) was shown to result in rapid cell surface expression of CD80, CD86 and DR antigen on the surface of normal human peripheral blood neutrophils. A distinct subpopulation (approximately 20%) of neutrophils appeared to be enlarged and were found to express significantly elevated levels of these molecules on the cell surface following cross-linking of CD11b when compared with control cells. The level of expression of CD80, CD86 and DR antigen on these large cells was comparable to, and in some cases greater than, the levels found expressed on the surface of monocytes obtained from the same donors. In addition, these cytoplasmic molecules were shown by confocal laser microscopy and by immunoelectron microscopy to be located within secretory vesicles. Following rapid translocation onto the cell surface, CD80 and CD86 appeared to be colocalized within large clusters reminiscent of the supramolecular antigen clusters previously found on conventional antigen-presenting cells. These findings therefore lend further support for the hypothesis that neutrophils may have a role to play in antigen presentation and/or T-cell activation. [ABSTRACT FROM AUTHOR]

The participation of oxidative mechanisms in major histocompatibility complex (MHC) class II-restricted antigen presentation was studied in vitro. In general, antigen processing is inhibited when peritoneal macrophages (MØ) are incubated with scavengers of reactive oxygen intermediates (ROI): mannitol (an ·OH scavenger), dimethylurea (DMTU, which reacts with H2O2 and HOCl) and NCO-700 (an epoxysuccinic acid derivative which inhibits oxidant production by activated phagocytes and can scavenge reactive oxygen species in both NaOCl and hypoxanthine (XOD) systems). However, neither rotenone and antimycins (inhibitors of O-2 production at the NADH dehydrogenase and ubiquinone–cytochrome b regions, respectively) nor aminoguanidine (an inducible nitric oxide synthase inhibitor) impaired antigen presentation, thus indirectly discarding the participation of mitochondrial oxidation and reactive nitrogen intermediates (RNI) in antigen processing. ROI scavengers do not inhibit the MHC class II-restricted presentation of antigens that need processing but have their disulphide bonds reduced. It can be shown that oxidation of protein antigens (either by chlorination or performic acid treatment) allow protein unfolding and enhance both processing and exposure of immunogenic epitopes to specific T cells. [ABSTRACT FROM AUTHOR]

The Fas (CD95) antigen plays a key role in regulating T-cell activation and survival. We have generated a Fas-resistant subclone of the human T-cell leukaemia line, H9, which is still able to undergo apoptosis in response to T-cell receptor ligation. Molecular analyses revealed that resistance to Fas-mediated apoptosis was due to a heterozygous mutation in the death domain of the Fas gene which generates a stop codon, and thus encodes a truncated Fas molecule. Fas ligation was able to induce apoptosis in the presence of cycloheximide, indicating that the mutant Fas molecule retained some signalling capability, which is death-domain independent. These cells will provide a useful tool for dissecting the complexities of Fas signalling pathways. [ABSTRACT FROM AUTHOR]

Highly purified CD4+ CD45RA+ cells from cord blood and peripheral blood from healthy adults were studied. The levels of expression of the CD2, CD3, CD4 and CD28 antigens were similar; however, CD45 and CD45RA antigen expression were slightly lower in cord cells. The reduced expression of the CD45RA antigen on cord CD4+ T cells was confirmed in whole blood. Functional assessment revealed deficiencies in cord CD4+ CD45RA+ T cells. Interleukin-2 (IL-2) production in response to specific triggering via CD2 monoclonal antibody (mAb) alone, or CD2 mAb in combination with CD28 mAb showed marked underproduction (about 10% of adult production). When CD25 expression was examined, it was observed that the proportion of activated CD4+ CD45RA+ T cells in cord blood was lower than in adult (about 20% of adult expression). Proliferation to CD2 mAbs or CD2+28 mAbs of cord blood naive cells was similarly depressed. Investigation of IL-2 mRNA expression under these stimulatory conditions paralleled the results observed for CD25 expression, IL-2 production and proliferation. When phorbol 12-myristate 13-acetate (PMA) was added to the cells triggered with CD2+28mAbs, the responses examined were enhanced in both cord and adult blood with no significant differences between the groups. These findings suggest that under identical conditions of stimulation, purified cord blood CD4+ CD45RA+ T cells do not acquire similar activation status as their adult counterparts. These finding may help in understanding the reduced graft-versus-host disease (GVHD) observed in cord blood stem cell transplantation. [ABSTRACT FROM AUTHOR]

In areas endemic for schistosomiasis, there is great heterogeneity in antibody isotype responses to parasite antigens amongst infected individuals. At the population level, the isotype composition of antibody responses undergoes dynamic changes which are associated with the age of infected individuals. Here we examine the IgG subclass responses to Schistosoma mansoni eggs (soluble egg antigens; SEA) of infected individuals by immunoblot and ELISA. By controlled treatment of SEA-coated ELISA plates and immunoblot nitrocellular strips with sodium periodate, in order to oxidize terminal carbohydrate residues selectively, we were able to relate individuals subjects' isotype responses to the different antigens that they responded to, and to the presence of putative carbohydrate and peptide epitopes on those antigens. IgG2 responses were restricted strictly to sodium periodate-sensitive carbohydrate epitopes and antigens of relatively high molecular weight. These antigens were not usually recognized by other isotypes and, therefore, they were only recognized by individuals who had high levels of IgG2. IgG1 and IgG3 responses were directed against both carbohydrate and peptide epitopes, whereas IgG4 responses were restricted to periodate-resistant epitopes. This suggests that the fall in IgG2 responses, and reciprocal rise in IgG4 antibodies, seen in young children as their intensities of schistosome infection increase, is not the result of isotype switching, and that, if these two subclasses are involved in blocking immunity to schistosomiasis, they are operating independently. [ABSTRACT FROM AUTHOR]

We have used the Galβ(l→3)GalNAc-specific Amaranthus leucocarpus lectin to isolate a thymus cell subpopulation which is different from that sorted with Arachis hypogaea lectin. The cells recognized by A. leucocarpus lectin were predominantly CD4+, whereas a minor proportion of CD8+ cells (approximately 11%) were also identified. The A. leucocarpus-positive cells were located in the thymus medulla and the cortico-medullary junction. The cortex was negative for A. leucocarpus cells. [ABSTRACT FROM AUTHOR]

A 180,000 MW molecule has been identified on porcine leucocytes that is the homologue of the 215,000/300,000 MW WC1 (T19) leucocyte antigen previously considered to be restricted to ruminants. In ruminants the WC1 molecule is expressed by a T-cell subpopulation that is CD2-CD4-CD8-CD5+ and that is γδ T-cell receptor positive (TcR+). In pigs, the 180,000 MW molecule, identified by a new monoclonal antibody CC101, is expressed by a γδ TcR+ T-cell subpopulation that is also CD2-CD4 CD8. The p180+ cells are a major T-cell subpopulation comprising approximately 40% of the peripheral blood mononuclear cells from 6-9-month-old pigs. Expression of p180 identifies the majority of the CD2-CD4-CD8- T cells in porcine blood. The p180+ T cells have a distribution in lymphoid tissues that is distinct from that oft cells that express the CD2, CD4 or CD8 molecules. They are evident particularly in the thymic medulla, the epithelium, lamina propria and interfollicular areas of the small intestine, and the superficial dermis of the skin, but largely absent from conventional T-dependent areas of secondary lymphoid tissue. [ABSTRACT FROM AUTHOR]

The aim of this study was to produce monoclonal antibodies (mAb) recognizing equine lymphocyte surface antigens. Fusions were conducted using BALBjc mice hyperimmunized with equine thymocytes. Hybridoma supernatants were screened by flow cytometry and positive hybridomas were cloned twice by limiting dilution. These mAb were then characterized for tissue distribution by immunohistology and flow cytometry, and by precipitation and analysis of the lymphocyte antigens which they recognized. Three mAb (CVS5, CVS4 and CVS8) are described which recognize only T lymphocytes in peripheral blood. Two-colour immunofluorescent studies showed that CVS5 recognized all T lymphocytes and that CVS4 and CVS8 recognized two mutually exclusive subsets of CVS5-positive cells. In the thymus there was a large population of CVS4/CVS8 double-positive cells. lmmunohistochemical staining with these mAb was restricted to T-lymphocyte areas. CVS4 and CVS5 precipitated molecules of 58,000 and 69,000 MW, respectively, in both reducing and non- reducing conditions. CVS8 precipitated two molecules of 32,000 and 39,000 MW in reducing conditions, and one molecule of 69,000 MW in non-reducing conditions. This evidence suggests that CVS5, CVS4 and CVS8 recognize the equine homologues of CD5, CD4 and CD8, and that the characteristics of these antigens are similar to those of other species. [ABSTRACT FROM AUTHOR]

Immunization of male rats and monkeys with gonadotropin-releasing hormone (GnRH) conjugated to a carrier results in a dramatic atrophy of the prostate. GnRH, linked to either diphtheria toxoid or tetanus toxoid as carrier, is now being evaluated for its use in the immunotherapy of hormone- dependent prostatic enlargement in men. This report deals with the phenomenon of carrier-induced, epitope-specific regulation in the GnRH-carrier system. In experiments designed to assess the influence of the carrier on antibody responses to the ‘self’ hapten GnRH, we show that preimmunization with carriers diphtheria toxoid and tetanus toxoid results in a strain-dependent inhibition of anti-GnRH responses in mice. Results of adoptive transfer experiments indicate that T cells from carrier-presensitized mice are responsible for suppression of anti-haptenic antibodies and that T cells from conjugate-immunized mice, on the other hand, can actually help overcome hyporesponsiveness. [ABSTRACT FROM AUTHOR]

A polyclonal anti-idiotype was raised in rabbits following immunization with a murine monoclonal antibody which recognized a 250,000 MW antigen of Plasmodium chabaudi-infected erythrocytes. The monoclonal antibody, NIMP M23 (clone 3,) has been shown to protect mice against homologous parasite challenge. Following purification, the anti-idiotype was shown to bind only the immunizing idiotype and to recognize antigen-binding site-associated anti-idiotype. Mice primed with anti-idiotype and challenged with live parasites had an altered course of infection, with significant reduction in their peak parasitaemia levels. Anti-idiotype priming did not induce an antigen-reactive antibody response in vivo but a population of T cells capable of proliferating in vitro to P chaubaudi-infected red cells was stimulated. These data are discussed in the context of possible idiotypic interaction in routine malaria. [ABSTRACT FROM AUTHOR]

The H-Y-expressing murine tumour, ET-5, specifically immunizes B6 female mice that have rejected it against H-Y-positive male skin grafts, yet fails to prime their spleen cells for the generation of H-Yspecific cytotoxic T lymphocytes (CTL). ET-5 also fails to prime relevant congenic hosts to generate CTL specific for H-3 or H-25 minor H antigens, or major histocompatibility complex (MHC) class I antigens, all of which are expressed in immunogenic form by ET-5. Nonetheless, C3H.SW mice, which are MHC-compatible with B6 mice in which ET-5 originated, but differ from B6 at many minor H loci, can be primed to generate CTL directed against one or more unidentified minor H antigens. These CTL are conventional MHC-restricted, CD8+ T cells, and require priming in vivo for their generation. Significantly, C3H.SW females can be primed by ET-5 to generate B6-specific CTL, but not H-Y-specific CTL. Thus CTL priming is selective in the sense that ET-5 primes CTL specific for some of the antigens it expresses but not others. The basis for this selectivity is not known but, in the case of H-Y antigen, it appears not to result from an inability of ET-5 to express either H-2Dbencoded antigens, the restriction element for H-Y-specific CTL in B6 females, or H-Y itself in vivo. [ABSTRACT FROM AUTHOR]

The effects of antigenic stimulation on the expansion of T-cell dependent areas in lymph nodes of mice were studied in relation to the effects on high endothelial venules (HEV) located in this area. Lymph nodes regional to areas of skin that had been treated with solutions of oxazolone were studied at several time-points after stimulation. The following measurements were made relative to lymph nodes of untreated animals: (i) the expansion of the T-cell dependent area in combination with the increase of HEV in this area, as detected by the HEV-specific mAb MECA-325, using morphometric analysis; (ii) the influx of FITC-labelled lymphocytes from the blood into the lymph node by FACS; (iii) the capacity of HEV to bind lymphocytes using an in vitro binding assay. Morphometry showed that T-cell dependent areas increased rapidly after stimulation with oxazolone and although the mean area of MECA-325-positive HEV had also increased, this increase lagged behind the expansion of the T-cell area. Therefore the amount of HEV per T-cell area in an antigen-stimulated lymph node was smaller than in an untreated lymph node and correlated with the percentage of FITC-labelled cells that had entered it. In a lymph node from an oxazolone-treated animal this percentage was decreased to the same order of magnitude as the area of HEV per T-cell area, but the overall binding capacity of HEV was not affected by oxazolone treatment. Antigenic stimulation therefore leads to a rapid expansion of the potential sites of lymphocyte entry into a lymph node, but the efficiency of the HEV does not change. [ABSTRACT FROM AUTHOR]

Immunogenic activity of a lipid hapten is strongly dependent on the length and nature of the linker chain (spacer) connecting the hapten to the head group of the lipid. A derivative containing a very short or a long spacer is known to be lass effective for antibody binding than that of an intermediate length. In the present experiment, this was confirmed first by experiments of antibody binding to TNP lipid haptens with different length of spacers and of antibody-dependent macrophage binding to them. Second, we determined the location of the TNP haptens in lipid bilayer membranes by fluorescence energy transfer. It was found that vertical distances between TNP groups (acceptors), which were assumed to be randomly distributed in a plan parallel to the membrane surface, and a pyrene fluorophore (donor), which was embedded in the middle of lipid membranes, were 10·2–10·5 Å in the DMPC membranes and 13·2–13·9 Å in the DPPC membranes. The vertical distances were about 3 Å longer in the DPPC membranes than in the DMPC membranes. However, they were almost independent of the length of spacers. This indicates that TNP residues of the lipid haptens locate at the similar vertical position on the membrane surfaces even if they have different length spacers. From these results we suggested that the affinity of the spacer groups to the bilayer surfaces can modulate the binding affinity of antibody to lipid hapten on the membrane surfaces. This was partly supported by the binding experiments of TNP spacers to the bilayer membranes. [ABSTRACT FROM AUTHOR]

Susceptibility to experimental autoimmune encephalomyelitis (EAE), which is an autoimmune disease inducible by immunization with a brain-specific antigen in complete Freund's adjuvant (CFA), is different among strains. In an attempt to resolve the immune mechanisms by which the difference in susceptibility to EAE is regulated, we re-estimated susceptibility of several strains of rats, and the frequency of antigen-reactive T cells in each strain was determined by limiting-dilution analysis. EAE was induced in Lewis (LEW), PVG/c and BN rats using four different methods: (i) active immunization with guinea-pig myelin basic protein (GPBP) in CFA; (ii) immunization with GPBP in CFA that had been further supplemented with Mycobacterium tuberculosis H37Ra (supplemented CFA); (iii) adoptive transfer of GPBP-activated spleen cells into syngeneic rats; and (iv) transfer of a GPBP-specific T-cell line. The LEW strain was susceptible to all four methods. The PVG/c strain was resistant to immunization with GPBP in conventional CFA (GPBP/conv. CFA), but was susceptible to immunization with GPBP in supplemented CFA (GPBP/suppl. CFA) and to transfer of activated spleen cells. The BN strain was resistant to all methods. Limiting-dilution analysis using T cells from LEW, PVG/c or BN rats has revealed that each strain of rat displays a different pattern of frequencies of GPBP-reactive or the 68–88 sequence (GP68–88)-reactive T cells. LEW rats showed relatively high frequencies of GPBP-reactive and GP68–88-reactive T cells after immunization with either GPBP/conv. CFA or GPBP/suppl. CFA, symptomatic rats showing higher values than asymptomatic rats. In asymptomatic PVG/c rats, the frequency of GP68–88-reactive T cells was lower than that of GPBP-reactive T cells. In PVG/c rats with clinical EAE, however, GP68 88-reactive T cells increased in frequency and were almost the same as GPBP-reactive T cells. BN rats, on the other hand, responded very poorly not only to the GP68–88 sequence but also to the whole GPBP molecule, even after immunization with GPBP/suppl. CFA. These findings, obtained by limiting-dilution analysis, strongly suggest that the development of EAE in LEW, PVG/c and BN rats is closely related to the frequency of GPBP-reactive T cells. Furthermore, it is shown that resistance to EAE found in PVG/c and BN rats may be generated by different immune mechanisms. [ABSTRACT FROM AUTHOR]

Histological examination of the lesions produced on the chick chorioallantois infected with cowpox virus shows extensive haemorrhage but there arc few inflammatory cells. However, infection with a deletion mutant, white cowpox virus, results in little haemorrhage but there is massive polymorpho-nuclear ceil infiltration. Extracts from tissues infected with the parental, red cowpox virus contained little or no chemoattractant activity detectable in micropore filter assays. However, white cowpox virus-infected tissue extracts, including cellular extracts from infected tissue cultures, had a marked effect in vitro on the migration of both neutrophils and monocytes. The chemoattractant activity induced in ovo by white cowpox virus infection has sedimentation characteristics in sucrose density gradients that are similar to leukotactic factors shown previously to be present in the allantoic fluid of chick embryos infected with paramyxoviruses. Induction of chemoattractant activity did not occur after infection of chick chorioallantois with a recombinant white cowpox virus constructed to express a protein that is responsible for the haemorrhagic character of red cowpox virus. This gene product has been shown previously to have homology with various serine protease inhibitors. The significance of these studies to the immunogenicity and pathogenicity of vaccinia recombinant viruses is discussed. [ABSTRACT FROM AUTHOR]

The relationship between the IgA antibody response in serum (total and polymeric IgA) and intestinal secretions was examined in volunteers subjected to oral and parenteral typhoid vaccination. After oral vaccination (three doses of 1011 live Ty21a vaccine given at 48-hr intervals), serum pIgA antibody to typhoid lipopolysaccharide (LPS) was detected in seven of the 14 subjects (46·4 ± 59 U,/ 100 μl, mean±SD). However, all 14 showed a significant intestinal IgA response (993±2516 and 9349 ± 6754 U/rag pie- and post-vaccine: t= 5·25. P= 0·0002). The level of pIgA antibody declined rapidly, whereas intestinal IgA antibody levels remained elevated. Serum pIgA antibody was also found after parenteral immunization (two doses of 5 × l08 heat-killed bacteria given 14 days apart to six subjects), but an intestinal IgA antibody response was detected in these individuals only after a subsequent course of the oral vaccine given I month after initial parenteral immunization. Changes in serum pIgA antibody followed those of total serum IgA antibody rather than those of intestinal antibody. The results indicate that a serum pIgA response can be induced by an antigenic stimulus delivered either orally or parenterally, whereas an intestinal IgA response is induced only by a local antigen stimulus, The regulation of serum pIgA and intestinal IgA appear to be independent. [ABSTRACT FROM AUTHOR]

Natural immunity to synthetic peptides (SP) derived from the sequences of a 3800 MW streptococcal antigen (SA) was found in human subjects. Significant serum IgG antibodies were detected both to the native SA and to peptides consisting of residues 3–13, l–15 and 1–20. Inhibition studies confirmed cross-reactivity between the native SA and SP. A series of short peptides with deletions at the amino and carboxy termini were then tested to determine the sequence of B-cell epitopes. Residues 8–13 and 1–6 bound significant serum IgG antibodies, but residues 8–13 were more effective and consistent in inhibiting human antibodies than residues 1–6. These results suggest that residues 8–13 constitute a major B-cell epitope but that residues 1–6 may represent a minor B-cell epitope. The human CD4 subset of T cells was then examined by stimulating the ceils with SA or SP and measuring the uptake of [3H] thymidinc ([3H]Td R). The cells were found to be sensitized in vivo to both the native SA and the SP and cross-reactivity between the SA and SP was shown by enrichment and depletion experiments on antigen-coated monocytes. As with the B-cell epitope, the series of short peptides was used to stimulate CD4 cells, in order to determine the T-cell epitope. Residues 6–15 were the shortest SP which stimulated significant [3H]Td R uptake and this peptide was designated as a T-cell epitope. The results suggest that natural oral immunization with Streptococcus mutans induces serum antibodies and T-cell sensitization to a peptide in which a T-cell epitope (residues 6–15) overlaps with a B-cell epitope (residues 8–13). Furthermore, a comparison between linear and cycled peptides suggests that unlike immunogenicity which is commonly enhanced by the more rigid cyclized peptides, antigenicity is favoured by linear peptides. This was evident not only for antibodies but also for T-cell proliferative responses. [ABSTRACT FROM AUTHOR]

Chlamydia trachomatis serovars release a glycolipid antigen (GLXA) into the culture supernatant during the infective cycle. This antigen is recognized by IgG isolated from humans with a natural chlamydial infection; GLXA may be a major antigenic determinant of chlamydia. It can be immunopurified by molecular shift or affinity chromatography. Silver staining of SDS-PAGE gels demonstrates a pattern of bands that is essentially the same for preparations isolated by either method. GLXA can also be extracted from mature elementary bodies (EB), These preparations show the same pattern of silver staining bands, and the major bands are immunoreactive as shown by Western blot analysis. Isoelectric focusing studies demonstrate that purified GLXA has an acidic pI. [ABSTRACT FROM AUTHOR]

Hepatitis B surface antigen (HBsAg) induced an immune complex-type hypersensitivity which developed at 5–6 hr after the challenge and could be transferred by anti-HBs antisera, in addition to the delayed-type hypersensitivity in B10.BR mice. The pre-S region of HBsAg influenced this induction because the pre-S-depleted HBsAg or recombinant major S protein could not stimulate this 5-hr car swelling. The male B10.BR mice responded batter than the female ones, probably due to the inhibition by female hormone. Furthermore, HBsAg could also induce an early-occurring hypersensitivity which appeared within 1 hr of the antigen challenge. However, B10.BR mice did not exhibit this hypersensitivity; B6 mice expressed all three types of hypersensitivity (1 hr, 5 hr and 24 hr) and BALB/c farce showed only 1-hr and 24-hr responses. The expression of the immune complex- type seems to be determined by the Ighb gene or gene(s) closely associated to it. Mice hearing the Igh-1b allotype could be stimulated by HBsAg to induce the immune-complex type hypersensitivity. Moreover, it was the high specific binding not the titre of anti-HBs antibodies that influenced the exhibition of immune complex-type hypersensitivity. [ABSTRACT FROM AUTHOR]

X-irradiated (250 rads) A mice injected with syngeneic trinitrophenylated spleen cells (Syn-TNP-SC) developed syngeneic delayed-type hypersensitivity (Syn-DTH) after footpad challenge with syngeneic concanavalin A-induced lymphoblasts (Syn-Con A blasts), as indicated by footpad swelling and lymph-node proliferation assays. Genetic analysis with different recombinant strains of mouse revealed that the H-2Dd subregion restricts these immunological activities. A small immunogenic entity was isolated from Syn-TNP-SC extract by gel filtration and affinity chromatography with anti-Dd antibody. X-irradiated A mice injected with this antigen also generated inflammatory responses after challenge with Syn-Con A blasts. Analysis of the data obtained from the gel filtration and the affinity chromatography suggest that the Syn-DTH-stimulating antigen is a fragment of the H-Dd heavy chain with a molecular weight (MW) of 5,000 to 10,000. This fragment does not contain TNP molecules or sugar moieties and neither does it express affinity for antibodies against class 11 products. Ltk- cells transfected with the H-2Dd gene also induced Syn-DTH in X-irradiated A mice, while the parent cells failed to stimulate such a response. Taken together these findings indicate that the selection process in the thymus is not absolute and T cells recognizing self-major histocompatibility complex (MHC) products do migrate from this organ to the periphery of the immune system. The possible biological significance of these autoreactive cells is discussed. [ABSTRACT FROM AUTHOR]

The idiotypic (Id) diversity of the immune response to phosphorylcholine (PC) was studied by immunization of mice with thymus-dependent (PC-keyhole limpet haemocyanin; PC-KLH) and thymus-independent (S. pneumoniae R36a; Pn) forms of the antigen. Mice with the BALB/c genetic background (BALB/c, C.B20, and BALB.B) were used because their response to PC is dominated by immunoglobulins encoded in VH-1 and Vk 22 genes, which uniformly express the T15 idiotype. The actual repertoire of the antibody was determined by idiotypic markers (Id) defined with monoclonal antibodies designated AB1–2, B36–82, MaId5–4, and B24–44. Previous studies from our laboratory have shown that these Id are present on TI5 (VS107-1/Vk22) immunoglobulins only, but that they differentiate between somatic variants of the antibody molecules. We have measured the serum concentrations of these four Id after primary (1°), secondary (2°), and tertiary (3°) immunization; all of the Id activity was associated with the PC-binding antibody, as shown by specific immunoadsorbents. However, the levels of the Id-bearing (Id+) antibody did not correlate with each other. After immunization with PC-KLH, the AB1–2+ antibody declined precipitously, whereas the levels of B24–44 and B36–82 remained steady. A similar pattern of Id heterogeneity was seen at the level of direct antibody-plaque-forming cells from the spleen, suggesting that the idiotopic (clonal) diversification occurred already during the early IgM response. A significant portion of anti-PC antibody after the 3° PC-KLH immunization was negative for all four Id, implying that the late response to the antigen involved distinct, T15-negative clones. The same idiotope repertoire changes were observed in BALB/c and in congenic strains C.B20 (Ishb) and BALB.B (H-2b). A diversification of T15+ antibody was also detectable upon immunization with a T-independent antigen, Pn, but to a much lesser extent. These observations indicate that the T15+ antibody response in BALB/c mice is heterogeneous, and that there appears to be a selection of specific clonal variants in which the T cells play a role. [ABSTRACT FROM AUTHOR]

The following fish orders, at different stages of phylogenetic development, were tested for serum antibody activity against actin, myosin, tubulin, thyroglobulin, haemocyanin, single-stranded DNA and trinitrophenyl (TNP): Elasmobranches (sharks), Chondrosteans (sturgeons), and Teleosts (bony fish). Significant antibody activity was found against all these self and non-self antigens but, in particular, high titres of natural anti-TNP antibodies were noted. Anti-TNP antibodies were then isolated by affinity chromatography from pooled sera of several representative fish species, and studied by a non-competitive and a competitive enzyme immunoassay. When the isolated antibodies were tested by the non-competitive assay, Teleost (tench) anti-TNP antibodies bound almost exclusively to TNP, whereas Chondrostean and Elasmobranche antibodies bound mainly to TNP but also to one or more other antigens. When the isolated antibodies were examined by the competitive assay, they could be separated into three groups: (i) anti-TNP antibodies whose binding could be inhibited by TNP only (Teleosts); (ii) anti-TNP antibodies mainly inhibited by TNP but also significantly inhibited by two or three other antigens (Chondrosteans); and (iii) anti-TNP antibodies binding to different antigens but only slightly inhibited by them (Elasmobranches). These antibodies were found by immunocytochemical staining to bind to normal cell constituents, and especially to cytoskeletal proteins. The results strongly suggest that natural antibodies against the seven antigens examined are present in normal fish serum, and that their specificities differ with the stage of phylogenetic development. [ABSTRACT FROM AUTHOR]