Induction of T15-specific suppressor T cells in mice with the CBA/N defect by neonatal injection with anti-T15 idiotype antibody

Mice with the CBA/N defect (xid) are unresponsive to phosphorylcholine (PC), To determine whether idiotype-specific suppressor T cells can also be generated in these defective mice, defective (CBA/N X BALB/c)F1 male and nondefective (CBA/N X BALB/c)F1 female or (BALB/c X CBA/N)F1 male mice were neonatally injected with antibodies specific for the major idiotype of anti-PC antibody, i.e., anti-TEPC-15 idiotype (T15id) antibody. Suppressor cell activity was examined by co-culturing spleen cells from neonatally treated F1 mice with spleen cells of normal nondefective F1 mice in the presence of antigen. Spleen cells from defective (CBA/NM X BALB/c)F1 mice treated with anti-T15id antibody demonstrated a level of suppressor activity (greater than 83% suppression) comparable to that of similarly treated nondefective F1 mice. This suppression was specific for the T15id of anti-PC response, and a Lyt-1-2+-bearing T cell population appeared to be responsible for the active suppression. These suppressor T cells recognized T15 but not PC, based on a functional absorption test. These results indicate that the CBA/N defects, including the deficiency in the anti-PC response by B lymphocytes and a possible T cell defect, do not influence the generation of T15id-specific suppressor T cells by neonatal injection with anti-T15id antibody.     

Differences in T15 expression of primary and secondary anti-PC responses with T cells from T15+ and T15- donors

The expression of T15 idiotype dominance with T cells from T15- mice was investigated. It was found that T15 dominance in the T-dependent response to phosphorylcholine (PC) could be generated by unprimed BALB/c B cells with T cells from T15+ and xid T15- mice. T15 dominance was also expressed when T15 neonatally suppressed BALB/c were used as T cell donors. With PC-primed B cells, however, T15 dominance was not established until 3 wk after adoptive co-transfer with T helper cells from xid NBF1 mice. To further study the different efficiencies of T cells for T15 dominance, limiting dilution analysis was performed. The data demonstrate that T15-specific T cell populations in BALB/c mice and NBF1 male mice differ in their precursor frequencies. In BALB/c mice, a frequent set of T15/M167-recognizing T helper cells is present; a corresponding frequent set of cells is absent in NBF1 males. This difference is likely to be one of the reasons why dominance is not immediately established after transfer of T cells from xid mice.     

Immune response to phosphorylcholine. VII. Functional evidence for three separate B cell subpopulations responding to TI and TD PC-antigens

A T-independent PC antigen, the C-polysaccharide, was used to induce a primary response to PC in splenic foci containing precursors taken from normal, unprimed BALB/c mice. The precursor frequency for the TI response was compared with the frequency for a T-dependent PC antigen, PPC-TGG-Hy. Idiotype analysis of the precursors for TD and TI responses indicate that the TD responses are more diverse with respect to clonal dominance of idiotype, TEPC-15, than that of TI responses. If splenic fragments were doubly immunized with both TI and TD antigens, the combined PC-specific precursor frequency was superadditive. TD-antigen-induced responses were found resistant to tolerogen and anti-idiotype suppression, whereas TI responses were extremely sensitive to both manipulations. Since under limiting dilution conditions precursors sort out independently, the superadditive response seen in dual immunized fragments can only be interpreted as evidence for an additional subpopulation of B cells that responds to the combined signals of TD and TI antigens. This postulated third B cell population is also extremely sensitive to tolerogen and anti-idiotype suppression.     

T cell-induced Ig allotypic suppression in mice. II. Both CD4+ CD8- and CD4- CD8+ T cell subsets from sensitized Igha mice are required to induce suppression of Igh-1b allotype expression

We established the phenotype of T splenocytes (Ts) from Igha/a BALB/c mice sensitized against B splenocytes from the Ighb/b CB20 congenic mice that induce Igh-1b (IgG2a of the Ighb haplotype) suppression. This was achieved by studying the action of anti-T cell subset mAb on the capacity of Ts to induce this chronic allotypic suppression in Igha/b (BALB/c x CB20)F1 mice. The Ts were treated with cytotoxic anti-mouse CD4 or anti-mouse CD8 rat mAb in vitro before their injection into the Igha/b newborns or in vivo after their injection into the Igha/b newborns. Exposure to either anti-CD8 or anti-CD4 mAb in vitro or in vivo leads to loss of the capacity of Ts to induce Igh-1b allotypic suppression. Mixing CD4+-cell-depleted Ts and CD8+-cell-depleted Ts preparations restored the capacity of the cells to induce Igh-1b suppression. Thus, both CD4+ CD8- Ts and CD4- CD8+ Ts are required for the induction of this allotypic suppression. Bone marrow cells and B splenocytes from Igh-1b-suppressed adult Igha/b mice were shown to be able to durably express Igh-1b when transferred into irradiated Igha/a BALB/c hosts whereas whole spleen cells from such donors failed to do it. Abrogation of Igh-1b suppression by in vivo anti-CD8 mAb treatment was achieved in adult Igha/b heterozygotes but with a lower efficiency than in adult Ighb/b homozygotes, all being chronically Igh-1b suppressed. The CD4- CD8+ cell population essential for maintaining this suppression is resistant to in vivo 600 rad irradiation and seems to be slightly inhibited by in vivo administration of free Igh-1b.     

Mechanisms of idiotype suppression. V. Anti-idiotype antibody inhibits early B cell triggering induced by antigen

To investigate the relationship between antigen-mediated B cell commitment and induction of idiotype (id) suppression, anti-id antibody directed against the major id (TEPC-15 idiotype or T15id) of the anti-phosphorylcholine (PC) antibody was added at various time intervals to BALB/c spleen cell cultures stimulated with a T-independent PC antigen, R36a. The suppressive effect of anti-T15id antibody on the anti-PC response was rapidly decreased as addition of the antibody was delayed; when anti-T15id antibody was added 6 hr after the initiation of the cultures, only partial suppression was induced, whereas the addition of anti-id antibody after 24 hr did not result in significant suppression of the anti-PC response when compared with similar cultures treated with mock anti-id antibody. This acquisition of resistance to id suppression was completely inhibited by treatment with either sodium azide or colchicine, as well as at temperatures below 20 degrees C. The induction of resistance to id suppression during the preincubation period was dependent on the presence of an immunogenic level of specific antigen. This antigen-mediated B cell commitment did not appear to require macrophages because preincubation of macrophages with antigen did not affect the sensitivity of the B cells to anti-id antibody. These results support the possibility that anti-id antibody inhibits early B cell triggering, which involves an energy-dependent, epitope-mediated, lateral mobility of antigen receptors possibly followed by repolymerization of microtubules.     

Suppressor T cells: presence in mice rendered tolerant by neonatal treatment with anti-receptor antibody or antigen.

Specific tolerance to phosphorylcholine (PC) was induced in BALB/c mice by two methods. Neonatal mice received a single injection of either: 1)PnC, the C-polysaccharide from S. pneumoniae, R36a vaccine which has PC as a major antigenic determinant or 2) ARA, an homologous antibody directed against the receptor for PC. Spleen cells from animals treated as neonates with either PnC or ARA were specifically suppressed for the response to PC antigens in vitro. In addition, cells from either group of unresponsive animals co-cultured with spleen cells of normal BALB/c mice markedly suppressed the response of the normal cells to PC. Greater than 90% inhibition of the plaque-forming cell response was obtained when unresponsive cells were mixed with normal cells in ratios of 1:1 or greater. Equal numbers of cells from animals made unresponsive by PnC or ARA produced an equivalent degree of suppression. Neither supernatants of cultures nor sera of animals of either unresponsive group suppressed the response of normal spleen cells to PC. Suppression by cells from both groups of tolerant mice was eliminated by treatment with anti-Thy 1.2 serum and C. Presumably, a common cell is responsible for suppression caused by cells from mice made unresponsive by either procedure.     

Coexistence of antigen-specific and idiotype-specific suppressor T cells in mice injected neonatally with a mixture of antigen and anti-idiotype antibody

Specific tolerance to phosphorylcholine (PC) can be induced in BALB/c mice by neonatal injection with either pneumococcal C-polysaccharide (PnC) containing PC or anti-TEPC-15 idiotype (T15id) antibody which recognizes the predominant idiotype of anti-PC antibody of BALB/c mice. Suppressor T cells (Ts) induced after treatment with anti-T15id antibody react with the T15id and PnC-induced Ts cells appear to recognize PC. A brief incubation of anti-id-induced, T15id-specific Ts with PnC-induced, PC-reactive Ts resulted in complete cancellation of their suppressor functions. However, both types of Ts were present in mice neonatally injected with mixtures of PnC and anti-T15id antibody. Neutralization experiments using either PnC-induced or anti-id-induced suppressor T cells strongly suggest that only one of the Ts cell types is functionally dominant in those mice: most frequently, T15id-specific Ts cells. The suppressor function of the other population is detectable only when the predominant Ts cell population is removed by anti-id or monoclonal IgM anti-PC (SP45) plus complement. However, both suppressor activities are completely eliminated when one of the Ts populations is removed by adherence to either antigen or T15id. These results suggest that mice neonatally injected with a mixture of antigen and anti-id antibody possess both types of suppressor T cells, yet only one type is functionally dominant.     

Perturbation of the idiotypic network. II. Transfer of suppression to neonatal mice

The cellular mechanisms which are responsible for idiotype perturbation induced by repeated stimulation with either allogeneic mixed lymphocyte culture-generated syngeneic blasts or allogeneically stimulated syngeneic spleen cells were investigated as described in the preceding article. Using the splenic fragment culture system, the precursor frequencies of T and B cells for anti-phosphorylcholine (PC) antibodies and T15 idiotypic antibodies were determined in allogeneically challenged mice. Adoptive transfers of T cells to neonatal BALB/c mice induced suppression of the T15+ anti-PC responses. In addition, the effect of immunization with internal image-bearing anti-idiotopes on the level of anti-PC antibodies and T15 idiotype was determined. Results from this study demonstrated (i) a decrease in the precursor frequency in the PC-specific and idiotype-specific B cell repertoire; (ii) a decrease in the precursor frequency of T helper cells, which recognize idiotypes and anti-idiotypes; (iii) the possibility to transfer T15 suppression to neonatal mice; and (iv) the possibility to restore T15 dominance by anti-idiotypic antibody immunization. These data indicate that both the T and B compartments are involved in the maintenance of suppression induced by repeated exposure to alloantigen-sensitized syngeneic cells. Collectively these findings show that a nonspecific general suppression induced by allohyperimmunization can perturb the T15+ anti-PC response.     

Tumor-specific immunity induced by somatic hybrids: III. Persistence of adoptively transferred immunity specific for TEPC-15 plasmacytoma in normal BALB/c mice

Immunity against TEPC-15 tumor cells was induced in BALB/c mice by injecting semi-allogeneic hybrid cells derived from fusion of TEPC-15 tumor cells with LM(TK^?) cells of the C3H origin. Adoptive transfer of spleen cells from the immune mice into normal BALB/ c recipients rendered them free from tumors following tumor challenge; the recipients were most significantly protected from the tumor when tumor cells were injected 7–14 days after the adoptive transfer of immune cells. Such immunity following adoptive transfer appeared to persist in the recipients for at least 60 days. Moreover, the tumor-specific immunity was consecutively transferable (more than nine passages) into normal BALB/c recipients by serially passing spleen cells from the recipients every 14 days, without further stimulation with the hybrid cells or inactivated TEPC-15 tumor cells. Such consecutive transfer of the immune spleen cells induced splenomegaly in the recipients: a two- to five-fold increase over normal spleen cell recipients. The ability of spleen cells to transfer immunity, but not splenomegaly, was abrogated by treatment with mitomycin C. These results suggest that proliferation of donor cells is necessary to transfer immunity, and that splenomegaly alone does not manifest such immunity in the recipients.     

Tumor-specific immunity induced by somatic hybrids. II. Elicitation of enhanced immunity against the parent plasmacytoma.

Hybrid cells derived from fusion of a BALB/c plasmacytoma (TEPC-15) and L cells (C3H origin) were used to stimulate tumor-specific immunity against the parental plasmacytoma cells. Live hybrid cells induced tumor-specific immunity against TEPC-15 more effectively than mitomycin-treated hybrid or TEPC-15 tumor cells. Adoptive transfer of immunity with spleen cells of mice immunized with hybrid cells was also more effective than that with mitomycin-treated tumor cells. The immunity induced by the hybrid cells was specific to the TEPC-15 tumor because the mice that received immune spleen cells were not protected against challenge with either HOPC-8 or McPC-603 plasmacytomas. T cell populations were primarily responsible for the transfer of specific immunity based on the sensitivity of immune cells to anti-Thy 1.2 and complement. Mice that had established solid tumors were treated with 5 x 10(7) spleen cells to evaluate the therapeutic value of the hybrid-induced immune cells. Tumors in the mice that received immune cells gradually regressed over a 40-day period, whereas tumors on the control mice continued to grow. These results suggest that a rearrangement of tumor-specific antigens on allogeneic hybrid cells can enhance their immunogenicity.     

Perturbation of the autoimmune network. II. Immunization with isologous idiotype induces auto-anti-idiotypic antibodies and suppresses the autoantibody response elicited by antigen: a serologic and cellular analysis

We report on the humoral and cellular events following autologous immunization against an idiotype (Id62) borne on a murine monoclonal autoantibody to thyroglobulin, and their impact on the autoantibody response to thyroglobulin. BALB/c mice with a state of active auto-anti-idiotypic immunity and challenged with thyroglobulin in complete Freund's adjuvant 2 wk after the last immunization with idiotype were found to have a suppressed autoantibody response. This suppression could be adoptively transferred to syngeneic x-irradiated recipients by using whole spleen cells from idiotype-primed mice. Transfer of separate T and B lymphocyte populations proved instrumental in disecting humoral from cellular events and in establishing that whereas B cells were required for transferring an intact anti-idiotype antibody response, T cells from idiotype-primed mice were necessary to transfer suppression. These findings contribute to our understanding of the interrelationship between antigen, idiotype, and anti-idiotype in the immune response to self-antigens, and the role of certain idiotypes in regulating autoimmune responses.     

Immune response to levan. II. T independence of suppression of cross-reactive idiotypes by anti-idiotype antibodies.

Pretreatment of BALB/c mice with antisera to a cross-reactive idiotype (E109IdX) expressed on many anti-bacterial levan (BL) and anti-inulin (Inu) antibodies leads to a prolonged suppression in production of IdX-bearing molecules in response to BL immunization. There is a comparable suppression in numbers of plaque-forming cells secreting IdX-bearing anti-BL and anti-Inu molecules. Furthermore, spleen cells from anti-E109IdX pretreated mice are unable to transfer to irradiated recipients the ability to produce IdX-bearing anti-BL and anti-Inu antibodies. These results indicate that the suppressive effect is at the precursor level and not simply a clearance of antibodies bearing the IdX. Suppression of IdX production can be achieved by pretreating nu/nu BALB/c mice with anti-E109IdX antibodies. Furthermore, spleen cells from pretreated mice do not inhibit the capacity of spleen cells from normal mice transferred to irradiated recipients to produce E109IdX in response to BL. This indicates that the suppression of IdX production in the anti-BL system is T independent and probably represents direct inhibition of precursors by anti-IdX.     

Perturbation of the idiotypic network. I. Induction with multiple alloantigen stimulation

The effect of hyperimmunization on the immune network with allostimulated syngeneic lymphocytes responding to different haplotypes was analyzed. Ten different haplotypes were used to stimulate syngeneic donor mice. Control mice were multiply immunized with incomplete Freund's adjuvant alone or with syngeneic mixed lymphocyte culture-generated lymphocytes. BALB/c mice were immunized consecutively with alloreactive blasts or allogeneically stimulated spleen cells at 10-day intervals. After a rest period of 2 months, the ratio of T helpers to T suppressors was determined by immunofluorescent staining. The functional network was probed by immunizing the mice with phosphorylcholine (PC) coupled to hemocyanin. The sera were analyzed for anti-PC antibodies and TEPC15 (T15) idiotypic expression. The results demonstrated (i) a decrease in the level of anti-PC antibody titer and T15 idiotypic expression; (ii) a decrease in the number of T helper cells and an increase in the number of T suppressor cells; (iii) a loss of PC epitope specificity; (iv) an increase of IgM antibodies expressing T15 without anti-PC specificity; and (v) an elevated level of preimmune lymphocyte proliferation and Ig secretion. These results reveal a functional network linkage in the regulation of alloreactivity and antigen response and show how repeated exposure to alloantigens can induce a perturbation of the idiotypic network controlling the response of a non-alloantigen-related BALB/c strain dominant idiotype (T15).     

Studies of CD4- CD8- alpha beta bone marrow T cells with suppressor activity.

The predominant T cell subset in the bone marrow of specific pathogen-free C57BL/Ka and BALB/c mice expressed the alpha beta+ TCR CD4- CD8- surface phenotype. Purified C57BL/Ka alpha beta+ TCR CD4- CD8- marrow cells obtained by cell sorting suppressed the MLR of C57BL/Ka responder and BALB/c stimulator spleen cells. Although the percentage of typical T cells in the spleen was markedly reduced in adult nude mice or normal neonatal mice as compared to the normal adult, the percentage of alpha beta+ TCR CD4- CD8- cells in the spleen and marrow was not. The percentage of "self-reactive" V beta 5+ T cells in the BALB/c spleen was markedly reduced as compared to that in the C57BL/Ka spleen. However, the percentages in the bone marrow were similar. The results indicate that the predominant subset of marrow T cells in these pathogen-free mice differ with regard to surface marker phenotype, function, dependence on the adult thymus, and deletion of certain self-reactive V beta receptors as compared to typical spleen T cells. The marrow T cells appear to develop directly from marrow precursors without rearranged beta chain genes during a 48 hour in vitro culture.     

Helper T lymphocytes from xid and normal mice support anti-phosphocholine antibody responses with equivalent T15, 511, and 603 idiotypic composition

We have examined the idiotypic composition of secondary adoptive transfer antibody responses to phosphocholine (PC) supported by KLH-primed helper T cells derived from normal mice or xid mice. CBA/N x BALB/c F1 male xid mice have diminished anti-PC responses and virtually undetectable levels of the T15 idiotype; xid mice do express the 511 and 603 idiotypes. Nonetheless, we find helper T cells derived from such mice are indistinguishable from T cells primed in a normal environment in their ability to cooperate with B cells producing anti-PC antibody bearing the T15, 511, or 603 idiotype markers. This result is in contrast to a previously published report from this laboratory. T cells from xid mice did support more IgG PFC than normal T cells, but serum IgG anti-PC antibody levels were similar in both groups. The IgM anti-PC response was predominantly of the T15 idiotype, whereas the 511 idiotype was associated with a minor fraction of IgG1 antibodies. The majority of the secondary IgG "anti-PC" antibody response bore none of the idiotypic markers associated with PC-binding myeloma or hybridoma antibodies, and was directed against phenyl-PC rather than PC. The phenomenon of T15 clonal dominance in the anti-PC response therefore is largely confined to the IgM response. We would conclude that the idiotype levels in the T cell priming environment do not influence the subsequent ability of such primed T cells to support anti-PC antibody responses.     

Thymus-independent induction and antigen-dependent recovery of idiotype-specific suppression

BALB/c nude (nu/nu) mice and euthymic (nu/+) littermates were treated as neonates with anti-T15 antibody and challenged at various ages with either a thymus-independent, PC-Brucella abortus (PC-BA), or thymus-dependent, PC-keyhole limpet hemocyanin (PC-KLH), form of phosphorylcholine (PC). Nu/nu mice challenged with PC-KLH received KLH-primed splenic T cells prior to immunization. Neither neonatally anti-idiotype-treated nu/+ nor nu/nu mice responded with the production of T15-positive anti-PC antibodies after challenge with either form of PC antigen. It is concluded that neither induction nor maintenance of a state of T15-specific suppression requires thymus-matured T cells. Recovery of anti-PC responsiveness in suppressed nu/+ or nu/nu mice was similar and was found to be related to the form of antigen used to elicit the response. Immunization with PC-KLH revealed a long-lasting unresponsiveness (up to 16 weeks). In contrast, immunization with PC-BA elicited a full anti-PC response as early as at 6.5 weeks of age.     

Idiotype shifts caused by neonatal tolerance to phosphorylcholine

The injection of as little as 0.5 microgram phosphorylcholine-(PC) conjugated mouse immunoglobulin into BALB/c neonates within 48 hr of birth results in complete unresponsiveness to PC for 3 to 4 wk. Thereafter, anti-PC responses can be detected in tolerized animals, but these responses differ significantly from those of normal BALB/c mice. First, the magnitude of responsiveness does not approach normal levels even 9 mo after birth. Second, although the initial responses as tolerance is broken can be T15+, idiotypic dominance is not established; instead, a heterogeneous T15- population eventually emerges, which includes clones with higher and with lower avidity than T15. Unirradiated unresponsive mice will help transplanted normal B cells to produce T15+ responses to thymus-dependent PC antigens. The responses of animals recovered from tolerance are stable upon adoptive transfer. We have, moreover, found no evidence of either loss of idiotype-specific T cell help or generation of suppression. Therefore, neonatal exposure to PC tolerogen can effect profound, permanent changes in the antigen-specific B cell compartment independent of any influence on conventional T cell regulatory mechanisms.     

Effect of passive administration of alloantiserum containing antibody against putative acceptor(s) for T cell-replacing factor (TRF) in the neonatal stage on development of B cell activity responsive to TRF

Previously, we showed that the antiserum raised in male (DBA/2Ha X BALB/c)F1(DCF1) mice (T cell-replacing factor [TRF]-low response animals) by immunizing them with activated B cells from BALB/c mice (TRF-high-responders) contained antibodies against putative TRF-acceptor site(s). We have now evaluated the hypothesis that neonatal treatment of mice with the above antiserum suppresses the development of B cells responsive to TRF. Male DCF1 mouse anti-BALB/c B-cell antiserum or normal DCF1 mouse serum as a control was injected into BALB/c mice within 24 hr after birth. In the antiserum-treated mice, no augmented primary immunoglobulin M (IgM) antibody responses to sheep red blood cells (SRBC) were observed under the conditions in which markedly augmented IgM anti-SRBC responses were induced in control BALB/c mice, suggesting that development of B cells reacting with male DCF1 mouse anti-BALB/c B-cell antiserum is suppressed by the neonatal treatment with the antiserum. Furthermore, the development of B cell activity responsible for helper factors derived from T cells, such as TRF, was markedly suppressed in the neonatally antiserum-treated mice, whereas activity of B cells capable of interacting directly with helper T cells through antigen-bridges was not significantly affected by the same treatment. Such suppression of the B cell activity could be induced only when the antiserum was administered within 48 hr after birth. Moreover, neonatal treatment of mice with the antiserum induced suppressed responsiveness of B cells to a T-independent type 2 antigen, TNP-Ficoll. Neither serum-borne suppressive serum components nor suppressor cells were detected by the system employed. These results support the hypothesis that TRF responsive B cells constitute a subpopulation distinct from the other B cells capable of cooperating with helper T cells via cognate interaction.     

Investigations into the nature of Igh-V region-restricted T cell interactions by using antibodies to antigens on methylcholanthrene-induced sarcomas. I. Analysis of an Igh-V-restricted suppressor-inducer factor

We have previously demonstrated the relationship between antigens on BALB/c methylcholanthrene (MC)-induced fibrosarcomas and T cell regulatory molecules by using a variety of antisera raised to these sarcomas in BALB/c and BALB/c X C57BL/6 (CB6F1) mice. One such pool of antiserum, a CB6F1 anti-CMS 4 (Pool XIV) serum, was used to investigate the nature of the T cell regulatory structures recognized by these antibodies. Pool XIV antiserum was capable of blocking the induction of feedback suppression by Ly-1 TsiF, an SRBC-specific suppressor T cell factor secreted by Ly-1+, 2- I-J+ T cells. Ly-1 TsiF induces suppression by interacting with an Ly-1+,2+ I-J+ T cell target. Successful interaction of Ly-1 TsiF with its target cell requires genetic homology between inducer and target cells at the variable region of the immunoglobulin heavy chain gene complex (Igh-V). The addition of Pool XIV antiserum to primary in vitro anti-SRBC cultures resulted in blocking the ability of Ly-1 TsiF from Igha (BALB/c) and Ighj (CBA/J) mice to induce suppression on syngeneic cells, whereas suppression induced by Ly-1 TsiF in Ighb (B6), Ighc (DBA/2), Ighd (A/J), and Ighe (AKR) mice are unaffected by addition of the Pool XIV antiserum. The ability of Pool XIV antiserum to block Ly-1 TsiF activity is linked to the Igh region, because Pool XIV antiserum can block Ly-1 TsiF from BALB/c (H-2d, Igha) and the Igh congenic B.C9 (H-2b, Igha) while not affecting Ly-1 TsiF activity on B6 (H-2b, Ighb) or its Igh congenic C.B20 (H-2d, Ighb). In CB6F1 animals, Pool XIV antiserum could block the ability of CB6F1 Ly-1 TsiF to suppress BALB/c spleen cells but not B6 spleen cells. Conversely, Pool XIV antiserum could block the ability of BALB/c Ly-1 TsiF to suppress CB6F1 spleen cells, whereas B6 Ly-1 TsiF showed normal suppressive activity in the presence of Pool XIV antiserum. In contrast, Pool XIV was capable of blocking the ability of Ly-1 TsiF from BALB/c into CB6F1 bone marrow chimeras (BMC) to suppress both BALB/c and B6 mice, whereas the activity of Ly-1 TsiF from B6 into CB6F1 BMC on BALB/c or B6 spleen cells was unaffected by the addition of Pool XIV antiserum. We then investigated the molecular nature of the molecule recognized by Pool XIV antiserum on the Ly-1 TsiF.(ABSTRACT TRUNCATED AT 400 WORDS)     

Regulation of T15 idiotype dominance. II. Genes unlinked to the Igh locus regulate T15 dominance of the secondary adoptive transfer response to phosphocholine

We have studied the idiotype and fine specificity of the secondary immune response to phosphocholine (PC) in C57BL (B10, B10.D2, and B.C8) and BALB (BALB/c, BAB-14, and C.B20) congenic strains of mice. In vivo IgM responses of mice from these two genetic backgrounds differed in their T15 idiotypic representation. BALB strains expressed the T15 idiotype on greater than 90% of their IgM, PC-specific plaque-forming cells (PFC), whereas C57BL strains expressed the T15 idiotype on approximately 50% of their IgM PFC. All strains examined expressed greater than 75% PC-inhibitable, VHPC idiotype-positive, IgM PFC. The IgG3 and IgA memory responses were similar to the IgM memory response; BALB strains produced a higher proportion of T15+ PFC than C57BL strains; however, the majority of IgG3 and IgA PFC in all strains were VHPC+, and PC-inhibitable. In contrast, the IgG1 memory response was not dominated by T15+, VHPC+, PC-inhibitable PFC in any of the strains tested. The IgG1 PFC required nitrophenylphosphocholine (NPPC) for efficient inhibition. The IgG2 memory response generally mimicked the IgG1 response with respect to idiotype and specificity. These data demonstrate that the representation of the T15 idiotype in the anti-PC immune response is determined by genes outside both the MHC and Igh genetic loci. Control of T15 expression in secondary IgM, IgG3, and IgA anti-PC responses was examined by using a cell-mixing protocol with primed T and B cells from BALB/c and B10.D2 mice. T15 representation in these responses was determined by the genotype of the B cell, not by the genotype of the helper T cell. Similarly, the B cell genotype was responsible for the idiotypic profile of a primary, in vitro, T-dependent, anti-PC response.