The behavior of hapten-poly-L-lysine conjugates as complete antigens in genetic responder and as haptens in nonresponder guinea pigs

Carrier function in anti-hapten immune responses. I. Enhancement of primary and secondary anti-hapten antibody responses by carrier preimmunization

Preimmunization of either guinea pigs or rabbits to bovine gamma globulin (BGG) prepares the animals for markedly enhanced antibody responses to 2,4-dinitrophenyl-BGG (DNP-BGG). This phenomenon is observed both in the primary anti-DNP antibody response to DNP-BGG and in the secondary anti-DNP antibody response to DNP-BGG in animals primed with DNP-ovalbumin (DNP-OVA). The BGG preimmunization is most effective if the antigen is administered as a complete Freund's adjuvant emulsion; in rabbits, a dose of 1 microg of BGG is more effective than a dose of 50 microg, whereas the reverse is true in guinea pigs. Transfusion of homologous anti-BGG sera fails to replace active immunization with BGG in the preparation of animals for these enhanced anti-DNP antibody responses. Both the immunoglobulin class and the average association constant for epsilon-DNP-L-lysine of the anti-DNP antibody produced in these enhanced responses is determined by the mode and time of immunization with haptenic conjugates and is not appreciably influenced by the nature of the carrier preimmunization. These studies indicate that the carrier specificity of hapten-specific anamnestic antibody responses is largely due to the interaction of two independent cell associated recognition units, one specialized for carrier and the other specific for haptenic determinants.

Carrier function in anti-hapten immune responses. II. Specific properties of carrier cells capable of enhancing anti-hapten antibody responses

Transfer of live lymphoid cells from BGG-immunized strain 2 guinea pigs into syngeneic animals primed with DNP-OVA prepares the recipients for a markedly enhanced secondary anti-DNP antibody response upon challenge with DNP-BGG. This phenomenon has been demonstrated when the recipients were challenged 1 day after cell transfer, but it was considerably more striking when an interval of 6 days was allowed between transfer of cells and challenge with antigen. As demonstrated in the preceding paper (6), BGG preimmunization enhanced anti-DNP antibody responses to challenge with DNP-BGG. An analysis of the characteristics of substances to which preimmunization was effective in enhancing subsequent anti-hapten responses was made. It was shown that preimmunization of strain 13 guinea pigs with a copolymer of glutamic acid and lysine (GL), to which these animals are genetically unable to accord an immune response, failed to prepare them for an enhanced anti-DNP response to DNP-GL. Tolerance to BGG specifically abrogated the capacity of subsequent BGG immunization to prepare DNP-OVA primed rabbits for an enhanced anti-DNP response to DNP-BGG. Sensitization of animals to haptens by preimmunization with hapten-protein conjugates failed to prepare them for enhanced primary or secondary antibody responses to other determinants associated with that hapten on a different carrier. These studies indicate that the enhancing effect of carrier preimmunization reflects a cooperative interaction between lymphoid cells specific for carrier and cells specialized for haptenic determinants. Furthermore, the capacity of a substance to behave as a carrier requires more than its possession of a variety of antigenic determinants.

Genetic control of the immune response of guinea pigs to limiting doses of bovine serum albumin: relationship to the poly-L-lysine gene

The response of strain 2 guinea pigs to limiting doses of bovine serum albumin is under dominant genetic control linked with the poly-L-lysine gene. Inbred strains 2 and 13 guinea pigs make similar antibody responses to 10 mug bovine serum albumin, whereas strain 2 but not strain 13 animals produce significant amounts of antibodies in response to 0.1 mug. The relationship between the presence of the poly-L-lysine gene and the ability to respond to limiting doses of bovine serum albumin has also been investigated in random-bred Hartley strain guinea pigs.

Genetic control of immunological responsiveness in guinea pigs to 2,4-dinitrophenyl conjugates of poly-L-arginine, protamine, and poly-L-ornithine

The ability of guinea pigs to respond immunologically to dinitrophenyl (DNP)-poly-L-arginine, DNP-protamine, DNP polyornithine, and to unsubstituted poly-L-arginine and protamine is linked to the presence of the poly-L-lysine gene. This gene has previously been demonstrated to control the immune response of guinea pigs to poly-L-lysine, to a copolymer of L-glutamic acid and L-lysine and to haptenic derivatives of these materials. Although the ability to respond to each of these highly charged compounds is linked to the presence of the poly-L-lysine gene, the cellular immune responses to these antigens is highly individually specific.

Transfer of responsiveness to hapten conjugates of poly-L-lysine and of a copolymer of L-glutamic acid and L-lysine to lethally irradiated nonresponder guinea pigs by bone marrow or lymph node and spleen cells from responder guinea pigs

Hartley guinea pigs genetically unresponsive to hapten-PLL (poly-L-lysine) conjugates were lethally irradiated and given allogeneic bone marrow from Hartley responder animals. Many of the animals died of graft versus host disease before their response to 2,4-dinitrophenyl-PLL (DNP-PLL) could be measured. The immune response of the surviving recipient animals was evaluated by anti-DNP antibody production, development of delayed hypersensitivity to DNP-poly-L-lysine, as well as by lymph node cell stimulation in vitro by this antigen. 12 of 14 recipient animals thus treated made an immune response as measured by 2 of the 3 parameters. Strain 13 guinea pigs, genetically unable to respond immunologically to DNP-PLL and to DNP-GL (2,4-dinitrophenyl-L-glutamic acid L-lysine copolymer) were lethally irradiated and given bone marrow from (2 x 13) F(1) responder animals or strain 13 bone marrow and (2 x 13) F(1) lymph node and spleen cells. A high proportion of the animals survived this procedure; no evidence of graft versus host disease was observed. Three of three strain 13 animals irradiated and, given strain 13 bone marrow and (2 x 13) F(1) lymph node and spleen, and then immunized with DNP-PL, made a specific immune response. 7 of 10 irradiated strain 13 animals given strain 13 bone marrow and (2 x 13) F(1) lymph node and spleen made an immune response to DNP-GL. However, only one of six irradiated strain 13 animals made a vigorous immune response to DNP-GL after reconstitution with (2 x 13) F(1) bone marrow alone. The ability to transfer the immune response to PLL antigens from responder to nonresponder animals demonstrates unequivocally that the defect in the non-responder animals is immunological rather than due to some other type of non-immunological mechanism. The bone marrow contains all the immunological cells necessary for the expression of the PLL gene. However, the finding that (2 x 13) F(1) lymph node and spleen cells were more effective than (2 x 13)F(1) bone marrow cell populations (known to be a rich source of monocyte precursors) suggests that the cells in which the PLL gene function is expressed may be lymphocytes rather than monocytes and macrophages.

Further evidence of third party unresponsiveness in immunologically tolerant animals

Three instances of third party unresponsiveness in immunologically tolerant mice are reported. Tolerance was induced across the H-2 barrier. Runt disease was prevented by the use of (host × donor)F₁ hybrid cells for tolerance induction. The rejection of third party grafts by F₁ hybrids from crosses between the host strain and the tolerance inducing donor strain excluded antigenic overlap as a possible explanation for the phenomenon.

Third party unresponsiveness was restricted to weak histocompatibility antigens. Skin grafts presenting the tolerant hosts with third party H-2 antigens were rejected with normal promptitude.

CBA mice tolerant of A, and A mice tolerant of CBA retained C3H grafts significantly longer than (A × CBA)F₁ hosts. It is suggested that this instance of third party unresponsiveness in reciprocally tolerant animals favours the interpretation that the phenomenon is due to incomplete specificity of induced immunological tolerance, rather than to an innate inability of the tolerant hosts to react against the relevant third party histocompatibility antigens.

The chemical nature of macrophage RNA-antigen complexes and their relevance to immune induction

10 different compounds, including natural and synthetic polypeptides, proteins, polysaccharides, amino acids, and steroid hormones, were assayed for their capacity to form complexes with peritoneal exudate cell RNA. Only molecules carrying negatively charged groups were able to do so. The formation of RNA-antigen complexes was unrelated to the immuno-potency of the "antigen," was not an enzyme-dependent reaction, did not require the synthesis of RNA following introduction of the antigen, did not seem to involve antigen-specific RNAs, was not specific for macrophages, since HeLa cells could be used as effectively, and occurred when purified RNA was mixed with antigen only in the presence of divalent cations. The complexes were very stable, once formed, but could be dissociated by exhaustive dialysis against buffers containing a chelating agent. The macrophage RNA-antigen complex therefore appears to be a chelate between anionic groups on the two components. Based on the total absence of a relationship between immunogenicity and the capacity to form such complexes, as well as the nonspecific nature of complex formation at every level examined, it appears unlikely that RNA-antigen complexes play a physiologically significant role in immune induction.

Selective immune reactivity to DNP-poly-L-lysine in randomly bred guinea-pigs

The specific immune response towards the synthetic antigen DNP—p(Lys) in randomly bred guinea-pigs has been investigated. A full immunological response, namely delayed hypersensitivity, PCA reactive, complement fixing and mercaptoethanol sensitive antibodies was obtained in nearly half the animals. The other half also showed an immune response restricted, however, to complement fixing and mercaptoethanol sensitive antibodies. Genetic heterogeneity of these animals with respect to immunization to DNP—p(Lys) was thus found to be reflected in the type of immune response induced rather than in an all or none reactivity.

The competitive effect of DNP-poly-L-lysine in responder and non-responder guinea pigs

The synthetic antigen DNP—p(Lys), which it is known to induce an immune response only in a certain percentage of randomly bred guinea-pigs, inhibited the immune response towards p(Tyr, Glu, Ala) and p(Tyr, Glu) synthetic antigens in all the guinea-pigs tested. The extent of the competitive effect was related to the quantity of DNP—p(Lys) injected.

The hapten moiety DNP—mono-lysine, had no inhibitory effect, while the p(Lys) carrier interfered with the response to p(Tyr, Glu), although to a lesser extent than did the complete conjugate.

The proportion of two b locus allotypic determinants in rabbit antisera raised against pneumococcal polysaccharide SSS 3 antigen

An agar gel radial diffusion technique has been devised to examine the amount of IgG and relative amounts of As 4 and As 5 in the sera of twenty heterozygous As/4,5 rabbits immunized with Type III pneumococci. Serial absorption of the sera with the polysaccharide SSS III antigen before reaction with anti-IgG and anti-allotypic sera was used to show how much specific IgG antibody was present in each serum and the distribution of this antibody between molecules bearing one or other or neither of the allotypic determinants.

The results indicate that anti-SSS III antibody generally occurred as As 4 rather than As 5 molecules although in some animals this preference was reversed. Non-allotypic (b-minus) molecules contributed significantly to the antibody response.

Distribution of antibody-forming cells of different specificities in the lymph nodes and spleens of guinea pigs

The distribution of antibody-forming cells of different specificities in the lymph nodes and spleens of guinea pigs immunized with two separate antigens or with antigens bearing two determinants was studied. When animals were immunized with two soluble protein antigens or antigens in which the two antigenic determinants were on the same molecule, antibody-forming cells of different specificities were always randomly intermixed. However, when animals were immunized with two heat-aggregated particulate protein antigens and then boosted with soluble protein antigens, cells of different specificities were often seen to occur in groups. These results suggest that antibody-forming cells may not arise by the antigen-stimulated proliferation of precommitted antibody-forming cells, but rather antibody-forming cells arise by a transformation of uncommitted precursor cells as the result of their interactions with a locally produced material derived from the processing of antigen.

Immune and non-immune responses to monovalent low molecular weight penicilloyl-polylysines and penicilloyl-bacitracin in rabbits and guinea-pigs

Rabbits and guinea-pigs have been immunized with low molecular weight penicilloyl—polylysines (BPO₁—PLL_{1 2}, BPO₆—PLL_{1 2}) with varying degrees of substitution and with monovalent penicilloyl—bacitracin (BPO₁—BAC). The immune response to the penicilloyl (BPO) determinant has been followed by skin tests, passive haemagglutination, passive cutaneous anaphylaxis (PCA), immunodiffusion and immunoelectrophoresis.

Maximally substituted BPO₆—PLL_{1 2} was found to be non-immunogenic. Apparently monovalent BPO₁—PLL_{1 2}, which inhibits precipitation of anti-BPO antibodies in vitro, was found to induce delayed-type hypersensitivity and antibodies for BPO in most of our random bred and in all strain 2 guinea-pigs. The delayed hypersensitivity in some of the sensitized guinea-pigs was hapten (BPO)-specific. BPO₁—PLL_{1 2} was very poorly immunogenic in rabbits.

Monovalent BPO₁—BAC induced BPO-specific delayed hypersensitivity and anti-BPO antibodies in some random bred guinea-pigs but not in strain 2 animals. BPO₁—BAC induced good levels of haemagglutinating anti-BPO antibodies in most random bred rabbits.

Truly monovalent compounds, such as BPO₁—BAC or BPO—ε-aminocaproate, do not elicit antibody-dependent reactions such as anaphylactic or Arthus reactions, but inhibit them.

On the other hand, apparently monovalent BPO₁—PLL_{1 2} was found to elicit BPO-specific PCA and Arthus reactions in immunized rabbits and guinea-pigs. When administered in higher doses, similar reactions were produced in non-immunized guinea-pigs. The possibility is discussed that some of the reactions observed with basic polypeptide antigens are due to the formation of mixed `specific antibody—polypeptide—non-specific protein' complexes formed in vivo by electrostatic interaction.

Hapten carrier relationships in the DNP-PLL foreign albumin complex system: induction of tolerance and stimulation of cells in vitro

Genetic nonresponder guinea pigs made tolerant to BSA and then immunized with DNP-PLL.BSA failed to make anti-DNP-PLL antibodies. Thus, tolerance to a carrier protein renders animals unresponsive to the hapten which it bears. The addition in vitro of DNP-PLL or DNP-GL to lymph node cell cultures derived from genetic responder animals immunized with these materials led to a significant stimulation of (3)H-thymidine incorporation into DNA. However, the addition of DNP-PLL or DNP-GL to lymph node cell cultures from nonresponder animals immunized with these materials failed to produce any stimulation of DNA synthesis. Furthermore, the addition of DNP-PLL to lymph node cell cultures from nonresponder animals immunized with DNP-PLL.BSA or DNP-PLL.OVA also failed to stimulate cell proliferation in spite of the fact that the lymph node cells of these animals were producing anti-DNP-PLL antibodies. The above facts suggest that the function of the PLL gene product is to act at an early crucial step in the immune mechanism to form an antigen-inducer complex. The specificity of this early step may be of a simple order and different than that of the antibody which is later produced in the immune response.

Studies on the relation of a prior immune response to immunogenicity

(1) Two polymers of D-glutamic acid, one synthetic (poly-α-D-glutamic) and the other the capsular polypeptide of Bacillus anthracis (poly-γ-D-glutamic), which did not induce detectable antibody when injected in saline, elicited precipitating antibody in rabbits when complexed with methylated bovine serum albumin (MBSA).

(2) Animals that had made an immune response to either of the polypeptides did not produce detectable anti-hapten antibodies when subsequently immunized with the homologus polypeptide conjugated with p-amino-ṕ-dimethylaminoazobenzene (PDA) groups. Neither was there an observable response to the polypeptide carrier.

(3) Hapten-specific antibody was elicited with an immunogenic carrier, hen egg albumin, and with the polypeptide—PDA conjugates complexed with MBSA, demonstrating that PDA could act as a determinant under the appropriate conditions.

(4) Rabbits that had made PDA-specific antibody were entirely refractory to polypeptide—PDA conjugate, inasmuch as their levels of anti-PDA antibody remained unchanged.

(5) It is concluded that the formation of antibody against a weakly immunogenic molecule does not alter the state of responsiveness of the animal upon subsequent contact with that molecule. Such a molecule cannot serve as a carrier for another structural determinant, either in animals that have made a prior immune response to the carrier or to the determinant.

A study of the passive transfer of delayed hypersensitivity to DNP-poly-L-lysine and DNP-GL in responder and nonresponder guinea pigs

A study of the passive transfer of delayed hypersensitivity to DNP-poly-L-lysine and to DNP-GL was performed in Hartley guinea pigs. Delayed hypersensitivity to DNP-PLL and DNP-GL could be transferred successfully only by means of sensitized cells from genetic responder guinea pigs and in most cases, only into those guinea pigs genetically capable of responding to PLL. The inability to transfer delayed hypersensitivity to DNP-PLL or DNP-GL to genetic nonresponder guinea pigs is not the result of the early destruction of the transferred cells by an incompatible host, since it was shown that delayed hypersensitivity to ovalbumin could be successfully transferred from guinea pigs with the PLL gene into genetic nonresponder animals. The requirement of active participation of specific and genetically controlled host mechanisms in the successful passive transfer of delayed sensitivity to DNP-PLL and DNP-GL has been demonstrated.

The immune response to a hybrid protein molecule; specificity of secondary stimulation and of tolerance induction

Upon immunization with LDH-III (subunit composition AABB) rabbits produce anti-A and anti-B antibodies in comparable amounts. These antibodies fit equally well to the hybrid enzyme and to LDH-V (AAAA) or LDH-I (BBBB) respectively, as tested by passive hemagglutination inhibition. No antibodies reacting with both LDH-I and LDH-V were detected. A minority of hybrid-specific antibodies was, however, present in the sera. Animals primed with LDH-III respond regularly to a boosting injection of LDH-V with the production of large amounts of anti-A (but not anti-B) antibodies. A similar injection of LDH-I stimulates (if it has any effect at all) the production of anti-B antibodies only. Stimulation with one of the pure types does not impair a subsequent response to the other. The majority of the animals primed with LDH-III responded not at all or weakly to a boosting injection of LDH-I, though antibodies to LDH-I were present in the sera at the time of stimulation. This effect can hardly be explained on the basis of serological sepcificity. Hyporesponsiveness to LDH-III can be induced by injection of LDH-V into the newborn. Both anti-A and anti-B titers are equally depressed. Within the dose range tested, LDH-I does not exert any tolerogenic action with respect to LDH-III. The carrier property of subunit A is evident in the induction of both immunity and tolerance to LDH-III. The early phase of the immune response to the hybrid enzyme may be carrier-specific, and receptors for the haptenic subunit B may not exist at that stage.

Inhibition, no-effect or enhancement of immune responses following injection of mixtures of immunogenic and non-immunogenic synthetic polypeptides

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.

Cellular localization of anti-DNP-PLL and anticonveyor albumin antibodies in genetic nonresponder guinea pigs immunized with DNP-PLL albumin complexes

Genetic nonresponder guinea pigs incapable of an immune response to DNP-PLL alone were immunized with DNP-PLL complexed to ovalbumin or bovine serum albumin. Under these circumstances the animals produce both anti-DNP-PLL antibodies and antibodies directed against the conveyor albumin. Thus immune response to DNP-PLL complexed to conveyor albumin molecules can serve as a simple model of hapten-carrier relationships. To explore these relationships the question whether these two types of antibody are synthesized by the same or by different plasma cells was investigated by a combination of a double immunofluorescent technique and radioautographic localization of radioactive antigen. It was shown that the anti-DNP-PLL antibodies and the antibodies against the carrier albumin molecule were produced in separate cells. No cell-producing antibodies with both specificities were detected out of 526 cells studied.