Idiotype-recognizing T helper cells that are not idiotype specific

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.

Expression of an interspecies idiotype in sera of SLE patients and their first-degree relatives

Sera from 29 SLE patients and 81 first-degree healthy family members were tested for quantitative expression of a cross-reactive idiotype present on a murine monoclonal anti-Sm autoantibody (Y2). Forty-one percent of SLE patients and 27% of all relatives showed increased serum levels of the Y2 idiotype compared to 6% in a normal, unrelated control group. In addition, female relatives of SLE patients showed slightly increased levels of anti-Sm antibodies compared to male relatives (15% vs 3%). In one of the 28 families and three unrelated SLE patients studied, there was a significant correlation between the Y2 idiotype expression and expression of another idiotype present on anti-DNA antibodies (1341d). Affinity column absorption studies showed that these two idiotypes were present on different antibody molecules. This study demonstrates: (1) a genetic predisposition for an anti-Sm antibody idiotype expression in humans; and (2) that two different idiotypes may be under parallel or coordinate regulation.

The induction of helper and suppressor cells with secondary anti-hen egg-white lysozyme B hybridoma cells in the absence of antigen

The results presented in this report define a dominant T cell-recognized public idiotype (SRId) expressed on monoclonal anti-chicken egg-white lysozyme (HEL) antibodies produced by hybridomas derived from secondary response lymphocytes. This Id mediates interactions between SRId+ B cells and SRId-recognizing T cells. In the absence of exogenous antigen, irradiated secondary anti-HEL B hybridoma cells (B-Hyb) of nonoverlapping specificity can be used to induce a helper T cell population capable of specifically stimulating an in vitro anti-HEL plaque-forming cell (PFC) response. Importantly, similar immunizations using carbodiimide-treated secondary anti-HEL B-Hyb cross-primed for a suppressor T cell population capable of suppressing this in vitro anti-HEL PFC response. That is, suppression was seen not only to the response induced by the homologous B-Hyb but to other B-Hyb which express anti-HEL monoclonal antibody of nonoverlapping specificity. This evidence is consistent with the presence of a pre-existent regulatory Id network involving SRId in antigennaive animals. After immunization with HEL, regulatory cells exert a strong selective pressure which leads to a secondary anti-HEL B population, of varying fine specificity, but uniformly positive for SRId.

Selective expansion of a CD3+CD4-CD8- subpopulation in clinical groups associated with human immunodeficiency virus infection

T lymphocytes (CD3+) without expression of CD4/CD8 surface antigens have recently been described in the thymus and peripheral lymphoid organs. We have conducted a retrospective analysis of the literature, seeking quantitative variations in this T-cell subset in normal heterosexual controls, and in risk, pre-AIDS, and AIDS groups, by means of the subtraction [CD3-(CD4+CD8]) and the ratio 100 X [CD3-(CD4+CD8])/CD3. Dramatic T lymphocytopaenia in AIDS patients and the progressive decay of CD4+ lymphocytes and increase of CD8+ lymphocytes throughout the clinical spectrum of HIV infection have been confirmed. Furthermore, we hereby demonstrate the selective expansion of CD3+CD4-CD8- lymphocytes, directly related to the clinical state in different clinical groups of infected people when compared with controls (P less than 0.05). The inverse relationship between the CD3+CD4-CD8- cell subset and other mature T-cell subsets, mainly CD4+ (r = -0.49; P less than 0.01), suggests the existence of mutual regulatory interactions. These in vivo results, which are in agreement with those obtained in long-term infected cultures, cannot be explained by direct cytopathic effects of the virus on the very few infected cells. Thus, the implication of the expansion of these functional precursors on the prognosis for infected people, and the paradoxes of the immunodeficiency, such as lymphoproliferation and autoimmune features, are discussed.

The basis for major histocompatibility complex (MHC) and immunoglobulin gene control of helper T cell idiotopes

BALB/c helper T cells, prepared against 2,4,6-trinitrophenyl (TNP)-derivatized syngeneic spleen cells, fail to recognize other hapten modifications [(4-hydroxy-3-nitrophenyl)acetyl, fluorescein isothiocyanate] of syngeneic cells, as well as TNP-derivatized cells from major histocompatibility complex-congenic donors. T helper cell interactions with "presenting" cells and "target" B lymphocytes are inhibited by monoclonal antibodies directed either to the hapten or to I-A molecules on target cells. Helper activity is also inhibited by monoclonal anti-idiotypic antibodies directed to an idiotope expressed by the TNP-binding myeloma protein MOPC460, but not by soluble TNP-protein conjugates. The study of congenic mouse strains revealed that while the fine specificity of TNP recognition and the quantitative levels of M 460 idiotope expression are I-A linked, the expression of the M 460 idiotope by helper cells is controlled by IgCh-linked genes. Absence of anti-idiotope inhibition of helper cells prepared in anti-mu-suppressed mice suggests, however, that immunoglobulin idiotype expression by T cells results from network interactions selecting available lymphocyte repertoires which operate before antigenic stimulation.

T-cell helper circuits

T helper cells specific for trinitrophenylated PC-binding myeloma and hybridoma antibodies are induced by priming with PC antigen, idiotype or anti-idiotypic antibody. These T helper cells are specific for a shared idiotope present on T15 and M167. Priming with the isolated heavy chains of T15 or M167, or the light chain of anti-T15 hybridoma antibody is equally effective in generating T helper cells. Evidently, the idiotope that is recognized by T cells is not dependent upon the conformation of the 7s Ig molecule. Collectively, these and other findings indicate the existence of a TH1-TH2-B cellular circuit which is based on the recognition of idiotopic determinants on T cell receptors. The implications of these findings in terms of network theory are explored.

Regulatory idiotopes. Induction of idiotype-recognizing helper T cells by free light and heavy chains

Previously, we have demonstrated the induction of T helper cells that recognize idiotype by antigen (19), idiotype (20), and antiidiotype (12). The T cell population has been characterized and found to recognize both the T15 and M167 myeloma proteins, which share PC binding specificity but differ in idiotypic specificities. In the present work, we used isolated heavy and light chains of T15 and M167 to generate T helper cells, and examined the response to trinitrophenyl (TNP)-T15 and TNP-M167. We found that the heavy chains induced a dose-dependent response to TNP-T15 and TNP-M167, while the light chain priming was ineffective. When isolated chains of a monoclonal anti-T15 antibody (F6-3) were used to induce idiotype-recognizing T cells, only the F6-3 light chains generated T cell help for TNP-T15 and TNP-M167. Evidently, the idiotypic determinant that is recognized by the T cells is not dependent upon the conformation of combined heavy and light chains. These data show that the Th2 helper cells for the T15/M167 idiotopes are induced by free heavy chains of T15 and M167; the Th1 T cells that interact with the Th2 population, of T15 and M167; the Th1 T cells that interact with the Th2 population, however, can be triggered by free light chains of an antiidiotypic hybridoma antibody. These provocative findings suggest a new model for the T helper cell network.