Search

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]

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]

Four experimental procedures leading to lower antibody production, namely administration of a minute amount of antigen or excess of antigen, competition with an unrelated antigen and treatment with methotrexate, were studied for their effect on each of the forms of immunological responses in guineapigs to a DNP-BSA conjugate. It was found that delayed hypersensitivity and 2-ME sensitive antibody production were more reduced by administration of excess of antigen or by competition than by giving a minute amount of antigen or methotrexate. On the other hand, IgG1 production was more suppressed in the groups receiving minute amounts of antigen or methotrexate treatment than in those given excess of antigen or subjected to competition. IgG2 production was markedly reduced in all four groups of animals. However, excess of antigen and competition changed the kinetics of both total antibody and IgG antibody production (peak on day 20 after immunization). The peak of total as well as IgG2 antibody-production in the groups given a minute amount of antigen or methotrexate, was on day 35, the same as in optimally immunized animals. These results suggest that a common mechanism for reduction of the immune response may be responsible for the excess of antigen and competition effects on one hand and the minute amount of antigen and methotrexate effects on the other. Competition with an unrelated antigen and excess of the same antigen could both act on the same effector cell. Methotrexate could act not only by killing a proportion of immunologically competent cells, but also by lowering their sensitivity to stimulation by antigen. [ABSTRACT FROM AUTHOR]

Albino guinea-pigs were actively sensitized with complete Freund's adjuvant. Tuberculin skin reactivity and tuberculin-induced in vitro mitotic responsiveness of circulating lymphocytes were determined sequentially in each animal after sensitization. In nine of ten animals studied, both skin reactivity and in vitro mitotic response to tuberculin appeared 3 weeks after sensitization. [ABSTRACT FROM AUTHOR]

Guinea-pigs injected with testis autoclavate (WT) in incomplete adjuvant develop antibody but no delayed hypersensitivity or testicular lesions. These animals fail to develop delayed hypersensitivity or a lesion when subsequently injected with antigen in complete adjuvant. Animals similarly treated, and then given repeated injection of immune cells from animals treated with whole testis and complete adjuvant, develop both delayed hypersensitivity and the characteristic orchitis. Guinea-pigs injected with a purified fraction (designated H) with incomplete adjuvant fail to develop either circulating antibody, delayed hypersensitivity or a testicular lesion. Animals subsequently injected with this antigen and complete adjuvant, develop delayed hypersensitivity but no circulating antibody or testicular lesion. Three of the five animals similarly treated and given repeated injections of serum containing anti-testis antibody also develop orchitis. A sequential study of fourteen animals killed at daily intervals after they were injected with WT and complete adjuvant, showed that antibody was first detected in the testis on the same day as delayed hypersensitivity first appeared. Circulating antibody was not detected until 2 days later. The specific testicular antigen showed first signs of disappearing on the 10th day, by which time histological evidence oforchitis was first detected. Antibody was not detected in the testes in any animal in the absence of delayed hypersensitivity. [ABSTRACT FROM AUTHOR]

Young immature guinea-pigs, 7–10 weeks old, were exposed to X-rays directed solely to the thymus gland which received a tissue dose of 300 r. An equal number of animals were not irradiated. All the animals had an intracardiac injection of 0·3 ml of Indian ink containing 10 per cent carbon of uniform particle diameter. An increase in number and size of Hassall's corpuscles was noted in irradiated thymus glands. Simultaneously, there was an increase in the uptake of carbon in the walls of blood vessels and in perivascular macrophages. Within 12 hours of irradiation Hassall's corpuscles contained carbon, at first in a finely stip- pled form in polymorphonuclear leucocytes and, later, in larger aggregates in macrophages. After an interval of 14 days Hassall's corpuscles disappeared and the lobules were re-populated with thymocytes. Migration outwards of carbon laden macrophages occurred between the 14th and 21st days. By contrast the entry of carbon in control glands took place more slowly but retention of particulate matter in Hassall's corpuscles was still present at the end of the experimental period of 56 days. It is suggested that Hassall's corpuscles are a ‘graveyard’ for dead thymocytes, possibly for some effete circulating lymphocytes and in some circumstances for polymorphonuclear leucocytes. It is also suggested that antigens localize in Hassall's corpuscles. Furthermore, since γ-globulin is known to localize there, these antibodies may be mobilized and returned to the circulation by macrophage activity. [ABSTRACT FROM AUTHOR]

The phenomenon of antigenic competition has been investigated by the use of synthetic compounds and guinea-pigs of inbred strain 2 as experimental animals. The effect of addition to the immunizing mixture of immunogenic and non-immunogenic synthetic compounds has been studied. Antigenic competition has been demonstrated between the synthetic antigen 252,p(Tyr,Glu,Lys) and DNP-p(Lys) or 28,pDLAla-p(Tyr, Glu)--pLys. The non-immunogenic compounds 251,p(DTyr,DGlu,DLys), 33,pTyr-pDLAla--pLys, and p(Tyr) have been found respectively to inhibit, enhance, or not affect the immune response to 252,p(Tyr,Glu,Lys). Two weak antigens, namely 509,p(Tyr, Glu,)-pDLAla--pLys and p(Lys) also enhanced the response to 252,p(Tyr, Glu, Lys). Possible explanations for these findings are discussed.

The immune response in guinea-pigs to linear and multichain copolymers of two, three or four different amino acids including tyrosine, glutamic acid, alanine and lysine, was studied. Delayed-type response was favoured in the case of preparations of relatively low molecular weight, containing only tyrosine and glutamic acid in their potential antigenic specificity determinants. Delayed sensitivity to one of these preparations was passively transferred with lymphoid cells. Antibody response resulted from the immunization of animals with preparations of relatively high molecular weight and with a more heterogeneous chemical composition. The antibody formation was intensified and accelerated, when p-azobenzenearsonate conjugates of the polypeptides were used as antigens. Variations in the immunizing dose had little or no effect on the nature of the reactions. A response of exclusively delayed type could not be intensified by repeated immunizations. The presence of mycobacteria in the immunizing injection was essential for the elicitation of the response to multichain, but not to linear copolymers. [ABSTRACT FROM AUTHOR]

Donor guinea-pigs were immunized with antigen in Freund's complete adjuvant. Three weeks later these donor guinea-pigs showed strong delayed hypersensitivity to the antigen. Peritoneal exudate cells (macrophages) and serum were then transferred intravenously from the immunized donors to normal recipients. Good 24-hour skin reactions were obtained in the recipients which had received cells and serum from donors immunized with bovine serum albumin, y-globulin, ovalbumin and haemocyanin. The reaction transferred by immune cells and serum was greater than the reaction transferred by either singly. This synergy was not found with PPD or blood group substance as antigen. Good transfers of 24-hour skin reactions to PPD were obtained with peritoneal exudate cells both alone and with serum. Good transfers could not be obtained with blood group substance. The synergic action of cells and serum in the passive transfer of 24-hour skin reactions was specific. The ability of peritoneal exudate cells to transfer 24-hour skin reactions was present at 1 week and greater at 3 weeks. In contrast the ability of serum to enhance passive transfers was absent at 1 week and present at 2 and 3 weeks. The histology of reactions passively transferred by spleen, lymph node and peritoneal exudate cells in the presence and absence of serum was studied. Serum alone produced a predominantly polymorphonuclear infiltrate which was maximal at 18-24 hours and almost absent at 48 hours. Cells alone produced only a very slight reaction. The combination of cells and serum produced lesions at 4 and 18 hours resembling those caused by serum alone. At 24 hours however the histiocytes and lymphocytes were more numerous than in the pure serum reaction and by 48 hours the infiltrate consisted of histiocytes and lymphocytes. It was concluded that, with certain antigens, there is a synergic effect of immune cells and serum in the passive transfer of 24-hour skin reactions and reasons are given for considering that these passively transferred 24-hour skin reactions are indeed delayed hypersensitivity reactions. [ABSTRACT FROM AUTHOR]

γG-globulins† from human syphilitic sera when treated with pepsin are still capable of flocculating cardiolipin antigen but lose their ability to fix guinea-pig complement in the presence of antigen. [ABSTRACT FROM AUTHOR]

Guinea-pigs were immunized by injections of blood group substance with incomplete adjuvant, followed after an interval of approximately 2 weeks, by intracutaneous immunization with the same antigen and Freund's adjuvant containing M. tuberculosis. This treatment inhibited the appearance of delayed skin reactions, while circulating antibody production took place as in controls which had received complete adjuvant only with blood group substance, and had delayed skin reactions. The inhibition of the skin reaction was found to be antigen-specific with regard to unrelated antigens, but showed cross-inhibition for serologically different human blood group substances. The first immunization had to be given more than 2 days before the immunization with complete adjuvant. A similar phenomenon was seen with ovalbumin as antigen. In addition to inhibition of the delayed skin reaction, there appeared to be less γ2-antibody to ovalbumin than in ovalbumin plus complete adjuvant-only controls. Passive administration of antibody did not affect the development of a delayed hypersensitivity state in complete adjuvant-immunized animals with blood group substance or ovalbumin as antigen. Present evidence favours an explanation of the phenomenon in terms of temporary paralysis on the part of some of the antibody-producing cells—viz. those concerned with delayed hypersensitivity and γ2-antibody production. [ABSTRACT FROM AUTHOR]

A method is described whereby biologically active H and L chains, free from each other by immunochemical criteria, can be prepared from guinea-pig γ2-immunoglobulin. The procedure makes use of mild reduction and alkylation in the absence of a denaturing agent, followed by gel filtration in the presence of 4 M guanidine-HCl. Specific binding of antigen by the method of equilibrium dialysis was found only when specific H chains were mixed with L chains, with more activity resulting when the L chains were also specific. Specific binding by antibody H chains alone was not found. [ABSTRACT FROM AUTHOR]

Groups of young adult rats were inoculated with bovine serum albumin in complete Freund's adjuvant into one foot-pad, a cervical lymph node, the spleen, a forelimb muscle, the cavity of the mediastinum or directly into the thymus. Arthus responses and circulating antibodies occurred in decreasing intensity in the order listed, but marked delayed sensitization resulted in the foot-pad and lymph node groups only. Groups of guinea-pigs were inoculated with egg albumin in complete Freund's adjuvant into a foot-pad, on the surface of the thymus or into the thymus. Delayed sensitization did not develop until the 17th day in the intrathymic group, and Arthus reactions and circulating antibodies were poor when compared with the other animals. Allergic encephalomyelitis was found in all seven rats injected with spinal cord and adjuvant in one foot-pad and in five of seven animals injected into a cervical node, while a single minimal lesion was present in one of twelve animals inoculated into the thymus directly. Plasma cells were seen in the thymus after injection of protein and adjuvant near the connective tissue of the capsule, the interlobular septa and blood vessels, whereas nervous tissue and adjuvant produced virtually no plasma-cell response. [ABSTRACT FROM AUTHOR]

Complement fixing reactions were observed between normal guineapig serum and antigens prepared from flukes of the genus Fasciola. This activity did of any other serum, and at the usual relative concentrations of antigen and serum, the guinea-pig serum was the limiting component. The effect therefore differ from a normal anticomplementary activity at the was termed the autofixation effect. In the presence of a gross excess of the antigen, the autofixation effect was inhibited. The antigenic component concerned was demonstrated in preparations from both Fasciola hepatica and F. gingantica, from adult and immature flukes, and from the metabolic products of F. gigantica. It was heat-stable and precipitated in 50 per cent ethyl alcohol, hut was soluble in water saturated with ether, Normal sent could be used to absorb the component out of the antigen. The autofixation effect summated with the normal anti-complementary activity of the antigens. In the 'Quantative Complement Fixation Analysis' type of complement fixation test, the control set up to allow for the anticomplementary activity of the antigen will also compensate for this effect. This does not apply with other forms of complement fixation test. [ABSTRACT FROM AUTHOR]

Passive cutaneous anaphylaxis in the guinea pig has been studied with rabbit antibody to a series of antigens of differing molecular weight. The results indicated that at a given antibody level the weight of antigen needed to elicit a reaction increases with its molecular weight. Previous observations have been confirmed that the amount of antigen needed to elicit a reaction at a high level of antibody is less than that required at a lower level. The results suggest that extremely small amounts of small molecular weight antigens might be sufficient to produce anaphylactic symptoms in highly sensitive individuals. [ABSTRACT FROM AUTHOR]

Previous findings of the appearance of pyrogenic activity when spleen and lymph node cells from BCG-sensitized rabbits were incubated with tuberculin in vitro have been repeated and extended in experiments with guinea pigs. Two different systems were used: hypersensitivity induced by BCG infection and by means of diphtheria toxoid-antitoxin precipitates. Cells were incubated in vitro with diluted tuberculin, diphtheria toxoid or Hanks's solution. Supernatant fluids obtained after various incubation periods were tested in normal guinea pigs for their pyrogenic activity and for ability to induce skin inflammatory reactions. Pyrogenic substances were obtained in most of the experiments in which cells of hypersensitive animals were incubated with the specific antigen; experiments with the unrelated antigen and controls were negative. Formation of skin-irritating substances was less regular, and they were sometimes formed non-specifically in control experiments also; in general, however, the results of these experiments agreed with the results of the fever reaction. The results obtained are discussed in relation to the mechanism of delayed hypersensitivity. [ABSTRACT FROM AUTHOR]

The capacity of denatured proteins to provoke anaphylactic sensitivity and delayed sensitivity in guinea pigs has been investigated. It has been found that heat-denatured proteins are as effective as native proteins in provoking delayed hypersensitivity to either material, in spite of the fact that such denaturation greatly modifies their antigenicity from the point of view of antibody production. Pure delayed hypersensitivity, moreover, occurs regularly in response to extremely minute amounts of a good antigen, whether native or denatured. It is further shown that immunological cross-reactivity can be demonstrated regularly by means of the delayed hypersensitivity reaction in guinea pigs, at a time when no cross-reacting antibodies of conventional type can be found. The significance of these observations in regard to the relationship between delayed hypersensitivity and antibody production is discussed. [ABSTRACT FROM AUTHOR]

Mast cell damage, characterized by loss of granules, occurs when the tissues of sensitized guinea pigs are brought into contact with antigen in vivo or in vitro. Quantitative studies on the mesenteries of passively sensitized guinea pigs show that the mast cell response to antigen is well correlated with the development of anaphylactic shock. After multiple sensitization contact with different antigens caused cumulative, but not complete, disappearance of mast cells. Antigen-antibody interactions, in which antisera were from species which do not sensitize guinea pigs passively for anaphylaxis, did not cause mast cell damage. Reversed passive anaphylaxis and mast cell damage were elicited when the antigen was a suitable γ-globulin, but not an albumin. Antiserum against homologous γ-globulin causes typical anaphylaxis and mast cell degranulation, whereas antiserum against Forssman antigen causes capillary damage without mast cell changes, and antiserum against homologous albumin is ineffective. These findings can be explained by the hypothesis that mast cell damage occurs as a result of antigen-antibody interaction, when one of the reagents is reversibly adsorbed at the mast cell surface, and when they are together capable of activating some process or agent whose further action depends upon the metabolic integrity of the cells. [ABSTRACT FROM AUTHOR]

Using the criteria of generalized anaphylaxis, the Schuhz­Dale test, and mast cell degranulation occurring on contact with antigen in vitro, a study has been made of the ability of antisera, prepared in various species, to sensitize guinea pig tissues passively. Whereas small amounts of guinea pig and rabbit antibodies and rather larger amounts of monkey, dog and human antibodies were effective, antibodies from goat, horse, rat, fowl and a human auto-immune thyroid antiserum were ineffective. These results are in general agreement with those in the literature. Using antibodies labelled with 131I, no gross differences were found between those which sensitized and those which did not, either in respect of uptake on guinea pig mesentery in vitro, or retention in the tissue after uptake in vivo. By means of antigen labelled with 131I it was also shown that the antibody adsorbed on guinea pig mesentery could combine equally well with antigen, whether the antibody came from rabbit (sensitizing) or rat (non-sensitizing). These experiments also indicated that the amount of adsorbed antibody necessary for sensitization is very small. Reversed passive anaphylaxis was studied with a variety of different antigen-antibody systems, using the criteria listed above. It occurred when, but only when, the antigen was a γ-globulin, and when both antigen and antibody globulins came from species whose antibodies were able to sensitize guinea pigs for direct passive anaphylaxis. It is concluded that the explanation of the differences between antibodies or antigens which sensitize guinea pigs passively, and those which do not, is to be found in the nature of the antigen-antibody combination as well as in the manner of ‘fixation’ on the tissues. The possible importance of ability to activate guinea pig complement is discussed. [ABSTRACT FROM AUTHOR]