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Small amounts of dinitrochlorohenzene (DNCB) in capsule from were fed to 63 adult male volunteers, following which these subjects and 60 control subjects were simultaneously subjected to a sensitizing series of topical applications of the same compound. After sensitization had been achieved, the level of sensitivity was inferred from a quantitative test series. Small amounts of DNCB appeared to have no effect on subsequent sensitization. When more than 20 mgm DNCB were given by mouth, however, a significant decrease in the ultimate level of sensitivity was seen. [ABSTRACT FROM AUTHOR]

Delayed skin hypersensitivity to specific antigen was enhanced when the antigen was given intradermally with Vibrio cholerae neuraminidase in sensitive subjects. No enhancement of skin test response was seen when inactivated enzyme was used. Neuraminidase exhibited no effect on negative skin-test response in non-sensitive recipients and no re!w1ion at the site of this enzyme was observed in any instance, suggesting that the enhancement effect is immunological in nature. [ABSTRACT FROM AUTHOR]

Chemically induced tumors of the rat submaxillary glands were tested for the presence of tumor antigens by in vitro leukocyte mediated cytotoxicity assays. Since it has been reported that the saliva of humans with oral cancer contains markedly elevated levels of secretory antibody, the rats' saliva specimens were also tested for blocking and/or potentiating ‘antibody’ activity. The results indicate that saliva from tumor-bearing animals potentiated tumor cell killing if either the tumor cells or leukocytes were pretreated. The effect was much more marked when tumor cells were pretreated. Furthermore, the addition of saliva to tumor cells imparted an immunologic cross reactivity which was not present with untreated tumor cells. Control saliva occasionally produced a similar effect, but not as consistently. or with the potency of saliva from tumor-bearing animals. Heat inactivation did not abrogate this potentiation. It is inferred that this may indicate a new system of immunologic surveillance, i.e. arming or potentiation of leukocytes by soluble tumor antigens in glandular secretions. [ABSTRACT FROM AUTHOR]

Bovine peripheral leucocytes were used in a migration inhibition test to detect sensitization to Theileria parva antigens. Seventy-six per cent of animals that were exposed to T. parva antigens yielded sensitive cells. The reaction was most efficiently induced by use of living T. parva. Migration of cells from control animals was not inhibited. In some animals the presence of sensitive cells in the peripheral circulation was shown m persist for up to 8 months after exposure to experimental T. parva infection. The significance of cells that are sensitive to T. parva antigens in East Coast fever is not known. [ABSTRACT FROM AUTHOR]

Thirty-five weak A samples including fourteen A3, eight Ax, seven Aend, three Am and three Am were studied in order to determine their A antigen site density, using an IgG anti-A labelled with 125I. The values obtained ranged between 30,000 A antigen sites for A3 individuals, and 700 sites for the Ae1 red cells. The hierarchy of values observed made it possible to establish a quantitative relationship between the red cell agglutinability of these phenotypes measured under standard conditions, and their antigen site density. [ABSTRACT FROM AUTHOR]

Poly A:U, a complex of synthetic polyadenylic polyuridylic acids, prevented tolerance induction to bovine gamma-globulin (BGG) in mice when administered 0-12 hours after a tolerogenic dose (500 µg) of BGG, as shown by haemagglutinin production and immune elimination of labelled antigen after challenge with 300 µg of aggregated BGG. Administration of poly A:U 3-6 hours after tolerogen appeared to be the most effective. It was found further that two doses of poly A:U given at 3 and 6 or 3 and 12 hours, or a double dose of 600 µg given at 3 hours after tolerogen did not increase its effectiveness beyond that of a single dose of 300 µg given at 3 hours. The finding that poly A:U, which may affect thymus-derived (T) cell function, prevented tolerance induction to a T cell-dependent antigen suggests that the action of poly A:U is on the T cell, For comparison, Salmonella endotoxin, thought to affect bone marrow-derived (B) cell function, was included and it interfered with tolerance induction when given 0-72 hours after soluble BGG. This interval is in marked contrast to poly A:U which is effective at 0-12 hours after tolerogen and probably reflects a difference in mechanism of the two agents. [ABSTRACT FROM AUTHOR]

The effects of Ca++ on primary and secondary immune responses to SRBC in vitro was investigated using the Marbrook technique. During the primary immune response three periods could be distinguished: first, a Ca++-independent lag period (0-24 hours after antigenic stimulation); second, a period with an absolute requirement for Ca++ (24-36 hours after antigenic stimulation), which is related to a proliferative phase of antigenically stimulated cells; and third, a period (later than 48 hours and up to 72 hours after antigenic stimulation), which is inhibited by Ca++ and which can be enhanced by removing Ca++ from the medium. This third period is related to the differentiation step(s) leading to antibody-forming cells. During the secondary immune response only a partial inhibition of immune response was observed after removing Ca++ from the medium at the time of antigenic stimulation. Addition of Ca++ to EGTA-containing culture medium at any time relative to the initiation of the secondary immune response enhanced the response, but, in contrast to its effects on a primary immune response, never completely restored it. Removal of Ca++ later than 6 hours after initiation of the response resulted in a decreased inhibition of the immune response and in an increased switch from 19S to 7S antibody-forming cells. This differentiation step was enhanced by removing Ca++ from the medium and was inhibited by Ca++ added to the medium. The results suggest that Ca++ controls the mechanisms involved in the antibody formation by an antagonistic action on cell proliferation and cell differentiation. [ABSTRACT FROM AUTHOR]

Immunological reactions, both immediate and delayed. were induced in guinea-pigs immunized with two sequential polyheptapeptides, poly-(Leu- Glu-Lys-Ma-Glu-Ser-Gly) and poly- (Leu-Glu-Lys-AIa-Glu-AIa-Gly). The serine-containing polymer was moderately efficient at inducing both types of immune response (7/16 immediate and 12/16 delayed), whereas the polymer containing alanine in place of serine was almost incapable of inducing a humoral response, but invariably induced cell-mediated immunity (1/15 immediate and 15/15 delayed) on primary immunization. The difference is attributed to the lower polarity of the alanine-containing polymer since other evidence exists indicating preferential stimulation of cell-mediated immunity with decreasing polarity of the antigen. [ABSTRACT FROM AUTHOR]

Chickens of four inbred lines were tested for the development of delayed hypersensitivity to mycobacterial antigens. It was found that WA and WB lines failed to develop tuberculin hypersensitivity. On the other hand, IB line was a strong responder, while the response of CB line was intermediate. [ABSTRACT FROM AUTHOR]

Antigen-induced migration inhibition of guinea-pig peritoneal cells was clearly detectable after in vitro irradiation with 5000 to 10,000 rads, but it was weaker than with non-irradiated cells. An attempt was made to quantify this effect by diluting immune cells with non-immune peritoneal cells. The titrations showed a drop of four two-fold dilution steps after 5000 rads and even 2000 rads caused a small drop to 50 per cent efficiency when compared to non-irradiated cells. [ABSTRACT FROM AUTHOR]

Tolerance to the parasitic nematode Trichuris muris was induced in mice by treatment with cortisone acetate given during the second week of a primary infection, the time at which the host is known to be beginning to respond to the antigens of the parasite. Continuation of the antigenic stimulus provided by infection beyond the period of immunosuppression was an essential requirement for tolerance; if the infection was terminated immediately after treatment the mice remained susceptible to subsequent infection, but then made a primary self-cure response. It is suggested that tolerance involves a long-lasting change in immunological reactivity of the host rather than a paralysis due to an excess of antigen, as tolerance was induced by small infections and persisted for at least 7 weeks in the absence of infection. [ABSTRACT FROM AUTHOR]

Anti-DNP-globulin from hyperimmunized rabbits was conjugated to ferritin by means of the bifunctional reagent, metaxylene diisocyanate. About 37 per cent of the antibody linked to ferritin was still able to combine specifically with the antigen, whereas no precipitating activity could be demonstrated. Data obtained in equilibrium dialysis experiments indicate an unchanged valency and affinity of those immunoferritin conjugates which remained active. [ABSTRACT FROM AUTHOR]

The physicochemical and biological properties of purified guinea-pig reaginic antibody were studied. It is a labile protein different to γ1. Its antibody activity is completely destroyed by heating at 56° for 6 hours and by treatment with mercaptoethanol. The capacity to give PCA is decreased by repeated freezing and thawing.It is a bivalent antibody, haemagglutinating, does not fix complement and is capable of sensitizing guinea-pig skin for PCA reaction after a latent period of a week but not after 3 hours. Reaginic antibody appears on day 7-8 after the first inoculation and the higher levels (PCA reaction) are obtained at the eleventh to thirteenth days. After the fifteenth to seventeenth days the PCA is negative. The reaginic antibody does not pass the placenta. Higher levels of reaginic antibody were obtained when the guinea-pigs were inoculated with the antigen in saline with simultaneous inoculation, intraperitoneally, of killed Bordetella pertussis, phase I. [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]

Antigens of algae in the genera Tetracystis and Chlorococcum have been studied extensively by immunodiffusion techniques. Some antigens were speeies-, group-, or genus-specific; others were common to both genera. The results largely supported other data from morphology, physiology, and ultrastructure but indicated a probable error in the taxonomic placement of one species. The cross reactivity between genera may be of importance in human, inhalant allergy to algae. [ABSTRACT FROM AUTHOR]

Two antigens of human wart tissue, a nuclear and a cell surface antigen, were isolated from whole tissue homogenates by elution from antibody-Sepharose immunoadsorbents. Neither antigen was a structural component of purified human papilloma virus. The antigens were detected by immunofluorescence in warts, squamous cell carcinomas, fetal skin, and psoriatic epidermis, but not in normal skin or basal cell carcinomas. They could be detected in concentrated extracts of normal skin by agar gel diffusion. The antigens belong to the growing class of substances that are readily detected in tumors and in fetal tissues, but are present only in minute quantities in normal adult tissue. [ABSTRACT FROM AUTHOR]

Presents information on a study which examined the response to enteric bacterial antigens in infants and to rubella vaccine in older children. Materials and methods used; Results; Differences in human immunologic responsiveness.

By selective nitration of egg-white lysozyme it is possible to obtain five lysozyme derivatives. Nitration of tyrosine 20 or tyrosine 23 slightly lowers the enzymatic activity and the thermal stability of the protein, modification of tyrosine 53 has a more drastic effect. Lysozyme nitrated on tyrosine 20 or tyrosine 23 loses one antigemc site. These two residues appear to belong to the same antigenic determinant, as lysozyme nitrated on these two tyrosines reacts with the same antibodies than the two former derivatives. Tyrosine 53 belongs to a second antigenic determinant of the enzyme, as it appears from the reaction between trinitrated lysozyme and the antilysozyme antibodies. [ABSTRACT FROM AUTHOR]

The article presents subject index for the journal "Clinical and Experimental Immunology." Some of the subjects included are: Allergen antibodies, a modified radioallergosorbent test for the in vitro detection of, 617; Anaemia, autoimmune haemolytic; Chromium survival studies in patients with different kinds of warm autoantibodies, 559; Antibodies and anti-kidney antibodies in kidney transplanted patients and patients with renal disease, occurrence and cross-reactivity of heterophile, 191; Antibodies to tubercle bacilli in sera from non-tuberculous and tuberculous individuals. Universal occurrence of, 65; Antilymphocyte globulin by human peripheral lymphocytes, uptake of, 423.

Haemagglutination inhibition experiments were used to study the interaction of several well-defined rheumatoid factors with pFá fragments ( = Cγ2 homology regions) prepared from all four IgG subclasses. The results suggest that rheumatoid factors interact with antigens located in both homology regions of the Fc fragment. A minimum of four reactive regions is suggested-one in the Cγ3 region and three more in the Cγ2 region. This multiplicity of IgG antigens may contribute to the formation of rheumatoid factor-IgG complexes and therefore play a role in the complement-fixing activity of such complexes. [ABSTRACT FROM AUTHOR]

A patient is described with macroglobulinaemia, a variety of autoantibodies, and gross deficiency of lymphocytes showing cytotoxicity against antibody-sensitized target cells in vitro. Antibody production in response to tetanus toxoid, delayed hypersensitivity to tuberculin, and lymphocyte transformation with phytohaemagglutinin are normal. The patient's macrophages have normal phagocytic activity against sensitized sheep red cells. These results are contrasted with those found in other patients with myeloma and macroglobulinaemia. The application of lymphocyte function tests in the assessment of immunological status is discussed. [ABSTRACT FROM AUTHOR]

Antibody activity against HSA and KLH was present in all five immunoglobulin classes of BALB/c mice. Bordetella pertussis vaccine was more effective in stimulating antibody production against HSA than against KLH and IgG1 and IgG2b antibody were affected more than the antibody present in the other immunoglobulin classes. The results are discussed in relation to the differing thymic dependence of these two antigens. [ABSTRACT FROM AUTHOR]

Samples of human blood-lymphocytes from patients with cancer, multiple sclerosis or cerebral haemorrhage were separated on a discontinuous Ficoll gradient. Six to eight fractions were obtained in which one or two fractions contained a large number of small lymphocytes. The fractions were incubated with encephalitogenic factor or tumour antigen and guinea-pig macrophages, after which the macrophages' electrophoretic mobility (EMR) was measured. The fractions with a density between 1-075 and 1 -090, and containing a high percentage of small lymphocytes, produced a significant EMR in these patients and it was concluded that the cells responsible for cellular immunological activity were also responsible for reductions in the electrophoretic mobility. [ABSTRACT FROM AUTHOR]

By means of the antigen-antibody crossed electrophoresis of Laurel! twenty-two different candida albicans precipitins were demonstrated in a serum from a 56-year-old woman suffering from idiopathic hypoparathyroidism and chronic candidiasis. This precipitin response is remarkably strong, but a detailed evaluation of the finding must await further investigations. lt is mentioned how the human precipitins may be quantitated and the titres expressed in arbitrary rabbit precipitin units. The antigen-antibody crossed electrophoresis may be useful in other infections, and possibly in certain autoimmune diseases, in order quantitatively to screen patient sera for a multitude of precipitins without purification of the individual antigens. [ABSTRACT FROM AUTHOR]

The article presents a discussion on antigenicity and autoimmunity in sexual reproduction. The immunology of reproduction is a growing field of research interest which seems to be developing a professional and scientific identity of its own as a sub-discipline that overlaps two major areas, namely, immunology and reproductive physiology. The antigenicity of spermatozoa was discovered in 1899 by means of immunization into a foreign species. Many studies were reported over a number of years with regard to the organ specificity and species specificity of spermatozoa. It is important to note that sperm cells contain at least two distinctive antigens, which are easily differentiated on morphological grounds, being characteristic of the head and tail parts of the cell.

In a model system, immune complexes formed in vitro (NIP-BSA conjugate/ anti-NIP antibody) were analysed by platelet aggregation (Pl.A.) and gradient centrifugation. The addition of specific antibody or antigen to immune complexes alters their composition towards different Ag/Ab ratios. This may result in increased, decreased or complete loss of Pl.A. titre Adding antibody to mixtures of free antigen and antigen excess complexes increased the Pl.A. titre greatly (⩾64-fold). The smallest complexes produced in antigen excess Ag/Ab>4 were only weakly Pl.A. active, and the complex could not be separated by gradient centrifugation from the free antigen. The S value of the complex with antigenic activity was greater than that of the original antigen. The titre of antibody excess complexes tended to decrease slightly after addition of low dilutions of antibody. Adding antigen to complexes produced smaller changes in Pl.A. titres than adding antibody. Pl.A. active complexes were also found after refractionation in sucrose gradient of a 20S complex (Ag/Ab∼4), but most of the activity was lost during manipulations. The lost activity could be restored by adding antibody. The possibility of using the Pl.A. technique and sucrose gradient centrifugation to detect and analyse natural immune complexes is discussed. [ABSTRACT FROM AUTHOR]

Using a local passive transfer system in mice it has been possible to detect interaction between sensitized lymph node cells and antigen inducing contact sensitivity. Cells were injected into the ears of mice intracutaneously and antigen applied to the skin. A late inflammatory" response at the site was detected by measuring the 24-hour uptake of 51Cr-labelled indicator ‘inflammatory cells’ (peritoneal exudate or oxazolone-sensitized lymph node cells). Three days after local transfer the uptake in ears receiving sensitized cells and challenged with antigen was three-to ten-fold greater than in the ears of animals receiving cells or antigen alone. This phenomenon was dependent upon challenge with the appropriate antigen. Interaction was also detected when cells were transferred into one ear and antigen applied to the other. Experiments to explain this effect showed that transferred cells disappeared rapidly from the site of transfer. Antigen applied elsewhere enhanced their mobility and increased their arrival at the antigen site. [ABSTRACT FROM AUTHOR]

Blood group HgA negative rabbits were injected with 2 x 109 HgA positive erythrocytes from a donor rabbit. Assortative matings were set up between those rabbits which produced detectable anti-HgA (responders) and those which did not (non-responders). The progeny were injected with 2 x 109 HgA positive erythrocytes 3 months after birth and their anti-HgA response measured. It was found that 20/24 (83 per cent) of the offspring of responder parents, but only 4/26 (15 per cent) of the offspring of non-responder parents, produced detectable anti-HgA. No difference was found between the ability of responders and non- responders to produce haemagglutinins to various doses of sheep erythrocytes. In contrast, non-responder rabbits rarely responded to non-HgA blood group isoantigens on the donor erythrocytes whereas rabbits which responded to HgA after injection of the donor erythrocytes often responded to non-HgA isoantigens. Typing the cells of non-responder rabbits with the sera from responder rabbits containing non-HgA antibodies showed that the non-responder cells were antigenically more like the donor cells than were the cells from responder rabbits. The ability to respond to HgA was not associated with any particular heavy or light chain immunoglobulin allotype specificities. It is considered that HgA has an important helper function in regard to the antibody response to non-HgA antigens but the latter probably also have a similar but less marked effect in relation to the HgA antibody response. The genetic control observed is thought to operate through T cell recognition and reaction with HgA and other blood group determinants. [ABSTRACT FROM AUTHOR]

Nuclei and nuclear membranes were examined for the presence of H-2 histocompatibility antigens in the mouse. These were detected on thymus as well as on liver preparations by means of 51Crk-cytotoxocity inhibition and complement fixation tests, absorption experiments and by the immunogenic properties of these preparations. [ABSTRACT FROM AUTHOR]

The contribution of syngeneic bone marrow and thymus cell populations obtained from normal and cortisone-treated donor mice for reconstitution of delayed hypersensitivity to methylatcd human serum albumin (MHSA) was studied in lethally irradiated recipients employing a limiting dilution assay. Normal thymus cells contained at least one antigen-reactive cell (or cell unit) per 3.7 × 107 cells, while cortisone-resistant cell populations contained one cell per 6.7 × 105 cells. Thus, cells immunocompetent to MHSA are not destroyed by steroid. Bone marrow cell populations contribute effector cells, and as few as 2 × 106 cells are capable of fully restoring delayed response when combined with optimum numbers of thymus cells. Large numbers of thymus cells alone will restore immune responsiveness, indicating that such populations do contain some effector cells, either as contaminating blood borne cells, or as glandular cells derived possibly from sinusoids. Similarly, bone marrow cells in larger numbers restore responsiveness, implying contamination with thymus-derived cells. [ABSTRACT FROM AUTHOR]

Activation of fresh blood lymphocytes has been measured by uptake of tritiated thymidine, following exposure to irradiated cells from autochthonous or allogeneic cell lines (LCL cells). Nine autochthonous combinations were studied. In every case activation was observed and in one the rate and peak level of activation were comparable to those found in control allogeneic mixtures. Neither foetal calf serum nor antibiotics appeared to be important factors in the activation process. There was no correlation between the number of identified HL-A histo-incompatibilities in a given allogeneic mixture and the rate or peak level of activation achieved. Activation appears to be influenced by the metabolic state of the LCL cells and the rate of the reaction is sensitive to the precise culture conditions under which it proceeds. Some distinction can be drawn between the antigens responsible for activation in autochthonous and in allogeneic mixtures but the former may prove to be modified histocompatibility determinants. [ABSTRACT FROM AUTHOR]

Cells from thirty-three human lymphoid cell lines and sublines have been typed for HL-A antigens by a microcytotoxicity test. Similar patterns of HL-A antigens were found for the cell line cells and for the fresh lymphocytes of the donor of the line (eleven cases). However, certain typing sera gave positive reactions with the cell line cells which were not found with the fresh lymphocytes. No correlation was noted between the pattern of these 'extra' reactions and the HL-A typing of the cells. These same typing sera often gave positive reactions with blood lymphocytes cultured for several days in conventional media. These positive reactions were quantitatively more pronounced and sometimes qualitatively different if the cells had been stimulated. A range of normal sera failed to react with cell line cells suggesting that the HL-A typing sera giving 'extra' reactions are detecting antigens in some way related to a histocompatibility system. Absorption studies performed with two of the lines confirmed the HL-A typing by the direct cytotoxicity test. Two sera giving 'extra' reactions were also tested in the absorption experiments. The results indicated that antibodies other than those of the HL-A specificity designated for these sera were responsible for the 'extra' reactions. It is suggested that 'extra' reactions indicate a change in the apparent antigenic expression of lymphoid cells reflecting altered membrane characteristics as they adapt to a culture environment. [ABSTRACT FROM AUTHOR]

Intact IgG antibody can terminate established immune responses, whereas F(ab')2 antibody cannot do so. The difference between the two antibodies appears to be qualitative. F(ab')2 antibody, but not pepsin-digested normal serum, can interfere with the suppression and termination of immune responses induced by intact IgG antibody. These results are discussed in terms of the tripartite inactivation model. [ABSTRACT FROM AUTHOR]

In order to determine the relationship between the level of circulating reaginic (IgE) antibody and degree of cutaneous hypersensitivity, rats producing different titres of reaginic antibody were assessed for skin test reactivity by means of the active cutaneous anaphylaxis test. Skin reaction diameters of ovalbumin-sensitive rats were similar whether they were producing low or markedly elevated levels of ovalbumin reagins. In rats infected with Nippostrongylus brasiliensis, skin test reactivity to N. brasiliensis antigen was demonstrable before reagin became detectable in the circulation. It increased to maximum shortly after the appearance of circulating reagin, and thereafter showed no significant increase commensurate with the further rise in reagin titre. The results show that in the rat there is no direct quantitative relationship between the size of skin test reactions and the level of specific circulating reaginic antibody. [ABSTRACT FROM AUTHOR]

Thymus or spleen cells obtained from foetal guinea-pigs have been exposed to phytohaemagglutinin (PHA) in cultures in vitro and in Millipore diffusion chambers implanted in the peritoneal cavity of adult guinea-pigs. As soon as enough thymus cells could be obtained for a culture (at 35 days post-coitus) PHA induced a small but significantly increased uptake of tritiated thymidine. No agerelated differences in the magnitude of the PHA response were observed. The proportion of blast cells in cultures was invariably increased by exposure to PHA. The time of appearance of PHA-responsive cells in the foetal development of the guinea-pig is in good agreement with results obtained in other species when compared by age-equivalence and provides an immunological basis for the resistance of foetal guinea-pigs to influenza virus. [ABSTRACT FROM AUTHOR]

Thermal regulation of the immune response was studied in toads following single injections of bacteriophage f2. The immune response was markedly inhibited in animals kept at 15° as compared to the controls (25°). The appearance of serum antibodies was delayed in animals kept at 15° for the first post-immunization week but their peak antibody levels were similar to those in toads maintained at 25° throughout. Transfer of animals from 25° to 15° 2 weeks after immunization only temporarily depressed the serum antibody levels but caused a marked delay in conversion from heavy to light antibodies. Our results are in keeping with the hypothesis that lowered environmental temperatures inhibit a variety of metabolic processes which may be concerned with the utilization of antigen and/or the synthesis of antibodies. [ABSTRACT FROM AUTHOR]

Antigenic determinants recognizable by rabbits were found to be present on the molecular fragments (48,000 Daltons) which were obtained by papain-solubilization of the membrane fractions of cultured human lymphoid cells and which carried the HL-A determinants. Results were obtained which suggest that these antigenic determinants are present in common on these molecular fragments carrying HL-A determinants regardless of their HL-A specificity and are restricted to the molecular fragments which carry HL-A determinants. The study was made by use of radioimmune methods involving the binding of radioiodine-labelled soluble HL-A antigen preparations by anti-HL-A alloanti- sera and by rabbit antisera raised against the membrane fractions of cultured human lymphoid cells. [ABSTRACT FROM AUTHOR]

A system is described with which an antibody response to soluble chicken ovalbumin can be obtained in dissociated spleen cell cultures from primed mice. This was assayed by determining specific anti-ovalbumin plaque-forming cells (PFC). Only IgG-producing cells (indirect PFC) were seen. The mice received alum-precipitated ovalbumin i.p. and cultures were set up either late in the primary splenic response (23–27 days after injection) or near the peak of the response (10–14 days). With both groups secondary responses were seen in the presence of antigen on the fourth day of culture. In the second group PFC were present in the cultures at a high level initially. The number of PFC de- creased over the first 2 days, the rate of decrease being greater in the presence of antigen. When mice were primed with alum-precipitated ovalbumin together with B. pertussis as adjuvant, responses could not now be obtained in culture. With mice taken late in the primary response (23–27 days), a considerable number of PFC were present in the cultures initially. The number decreased throughout the 4-day period and the decline was accelerated by antigen. With mice taken near the peak of the response (10–14 days) no PFC were seen in culture, even on the first day, in the presence or absence of antigen. The first phenomenon, suppression by antigen, is considered to be of general significance since it may also be seen in cultures from mice receiving no B. pertussis as described. It is suggested that the second phenomenon is due to adverse culture conditions resulting from the white cell mobilization initiated by B. pertussis; after 23–27 days conditions have recovered to a point where suppression but not the secondary response can occur. The suppressive effect of antigen could be related to antigenic competition or tolerance. [ABSTRACT FROM AUTHOR]

Three different types of antigenic determinants were demonstrated in soluble collagen with the aid of rat, rabbit and chicken antisera to native collagen. Helical antigenic determinants which require an intact triple-helical structure of the molecule are mainly recognized by rat antisera. Renaturation of the serologically inactive unfolded polypeptide chains (denatured collagen) is accompanied by a significant recovery of serological activity. Central antigenic determinants which are probably located in the same regions of amino acid sequence are less accessible in the native antigen and become exposed upon denaturation. Equal titres for both types of determinants are found in chicken antisera. Immunization with denatured collagen, however, revealed a response restricted to the central type. Isolated antibodies specific for terminal non-helical antigenic determinants, as yet only known to occur in rabbit antisera, reacted equally well with native collagen, the unfolded polypeptide chains and with small cyanogen bromide peptides. Independence of conformation is therefore suggested for these antigenic structures. [ABSTRACT FROM AUTHOR]

The effectiveness of antigen aerosol-induced desensitization has been investigated in guinea-pigs actively sensitized with antigen, alone or incorporated in Freund's adjuvants. Rates of desensitization, and the ability of animals to regain anaphylactic hypersensitivity following intensive desensitization, have been considered in terms of relative rates of antibody production, levels of circulating antibody, and qualitative differences in the antibody produced. A protective component observed during desensitization in adjuvant-treated animals is considered to be a property both of high levels of circulating antibody and of the presence of certain non-specific factors which interfere with the sensitization process. [ABSTRACT FROM AUTHOR]

The immunogenicity of a series of dodecapeptides was evaluated in random-bred guinea-pigs. The peptides were synthesized by an economical two-phase approach specifically developed for the production of gram-amounts of peptide antigens. The peptides contain L-leucine, L-alanine, glycine and L-lysine and differ from each other by number and distribution of lysine residues. Some of the peptides carry DNP groups at their N-terminus. With the exception of one (5,11-Lys2-LAG12-OEt), all peptides induced a state of cellular immunity as evaluated by delayed dermal reactions and macrophage migration inhibition. Some peptides also induced the formation of circulating antibodies, immunogenicity appears to increase with the number of basic groups and is more pronounced with DNP peptides. Delayed dermal responses are highly specific since even peptides closely related to the irnmunogen did not elicit reactions. Reactions were however observed when some mixtures of closely related peptides not used for immunizing the animal were administered. This 'antigenic cooperation' effect is discussed briefly. [ABSTRACT FROM AUTHOR]

Immunochemical identification of a distinct immunoglobulin class associated with mouse reaginic antibody and designated IgE has been performed. An antiserum against mouse reaginic antibody was prepared in rats by immunization with homologous peritoneal mast cells sensitized with mouse reaginic antibody. This antiserum, after adequate absorption, recognized only one component existing in mouse serum or fractions of serum containing reaginic antibody. This component was not any of the already known γ1, γ2, IgA or IgM immunoglobulins; its immunoglobulin nature was indicated by its antigen-binding capacity in radioimmunodiffusion analysis. Fractionation experiments (zone electrophoresis, gel filtration on Sephadex G-200) showed that there was a strict association between reaginic anaphylactic activity and IgE immunoglobulin. Molecular weight of IgE was found to be about 200,000. In biological tests, anti IgE neutralized anaphylactic activity attributed to reaginic antibody, but not that attributed to γ1-antibody. Anti-IgE degranulates normal and sensitized mouse peritoneal mast cells, and rat peritoneal mast cells after they have been sensitized by mouse reaginic antibody. [ABSTRACT FROM AUTHOR]

Cross-reactions between immunoglobulins from twelve mammalian species were observed by immunoelectrophoresis with antisera prepared in rabbits against the purified IgG of each species. The Fc fragments of the IgG from man, pig, goat, sheep and cow, were compared by examination of the cross-reactions before and after absorption of the antisera with the various IgG. Eight antigenic determinants could be detected; some of them were species-specific, others were shared by IgG from two or more species. A close resemblance was found between goat, sheep and cow IgG. [ABSTRACT FROM AUTHOR]

Complexes of Haemophilus influenzae cells with and without intact capsular material were prepared with type specific antisera. Thin sections of positively stained specimens were prepared and examined in the electron microscope. In the absence of capsular material the antibodies were observed bound close to one another in the immediate area of the bacterial cell wall. When capsular antigen was present the antibodies were farther separated from one another in the complex and appeared to be attached at random sites along the capsular polymers with occasional individual particles being observed. This positive staining approach appears to be a useful method to observe the molecular structure of precipitated immune complexes. [ABSTRACT FROM AUTHOR]

An analysis was made of the antibody response in the spleen and lymph nodes of mice to erythrocyte antigens injected under conditions which have been reported to cause antigenic competition. In the spleen, injection of a different erythrocyte antigen 2-4 days before the injection of a test antigen had little or no effect on the total number of cells or the number of plaque-forming cells (PFC) to the test antigen. Examination of the antibody response in opposite lymph nodes of a mouse made possible a comparison between two different conditions of antigen exposure within the same individual. In the lymph nodes, preceding the injection of the test antigen by an injection of a different erythrocyte antigen 2-4 days earlier led not to a decrease, but, on the contrary, to an increase in the number of plaque forming cells to the test antigen. A similar increase in the number of plaque-forming cells per lymph node was observed for each of two test antigens, when these had been mixed and injected into the forefeet 24 hours after the injection of a different erythrocyte antigen. [ABSTRACT FROM AUTHOR]

In fifty-five rheumatoid arthritis sera with positive granulocytespecific antinuclear factors (GS-ANF) tests were made to further characterize these antibodies. All sera contained GS-ANF of the IgG class and most of the sera also of the IgM and IgA classes, whereas only about 10 per cent of the sera contained GS-ANF of the IgD class. Most of the sera contained GS-ANF carrying both κ and λ light chain determinants, but in five cases only one of the light chain subclasses could be found. The distribution of the GS-ANF among the four subclasses of IgG showed marked variations. From one to three subclasses could be lacking or noticeably depressed. There was no predominance of any one or two subclasses. Complement (C3) fixing properties correlated with GS-ANF of the IgG1 and/or IgG3 subclasses. These properties make the GS-ANF interesting as possible pathogenic factors in rheumatoid arthritis. Some evidence is presented that the GS-ANF may be directed against several different antigens in the polymorphonuclear granulocyte nuclei. [ABSTRACT FROM AUTHOR]

A radioimmunoassay for the quantitative determination of the immobilization antigens of Paramoecium is described. The use of this technique in the identification of closely related antigens is discussed in terms of antigen 'profiles', derived from precipitin tests with several antisera. [ABSTRACT FROM AUTHOR]

The localization of antigen in actively immunized rabbits was not different from that in passively immunized rabbits, confirming that trapping of antigen is antibody dependent. The sequence of events following a single antigen injection shows that the antigen trapping in the germinal centre cannot be responsible for either the germinal centre reaction or the initiation of the antibody production. It was established that two non-cross reacting antigens were trapped in the same spleen follicles if specific antibodies against both antigens were present in the circulation at the time of injection of the antigens. [ABSTRACT FROM AUTHOR]

The distribution of viral antigens was determined in lungs, spleen and bronchial lymph nodes of a non-lethal primary Sendai virus infection of mice. Immunofluorescent staining showed that virus was initially confined to the bronchial mucosal columnar cells. Most antigen was present in this location between the 3rd and 5th days a finding which correlated well with infectivity assays. From the 3rd day desquamated mucosal cells in the bronchial lumen showed relatively weak staining for viral antigens. Alveolar macrophages were shown to contain viral antigens only after mucosal shedding had occurred. Viral antigens were found in bronchial lymph nodes between the 3rd to 9th days, and in the spleen from the 3rd day to 49th day after infection. Virus could not be grown from the spleen at any time. It was shown that the intraluminal cellular debris which appeared to contain little virus was coated with immunoglobulin. More viral antigen could be detected in this location after acid and alkali elution and after prolonged incubation with a potent heterologous anti-viral antiserum. It was concluded that early mouse antibody was fixed to viral antigens in the lung 3 days after infection and 5 days before it could be detected in serum or bronchial secretions. The significance of these findings was discussed. [ABSTRACT FROM AUTHOR]

Studies the foci of antibody-producing cells to two distinct somatic antigens present on one bacterium. Kinetics and nature of antibody focus; Effect of the physical nature of the antigen on foci formation; Distribution of foci in the spleen during the primary response; Inhibition of foci by antiglobulin sera or excess antigen.