Evidence for mouse Th1- and Th2-like helper T cells in vivo. Selective reduction of Th1-like cells after total lymphoid irradiation

Purification of murine suppressive factor of allergy into distinct CD23-modulating and IgE-suppressive proteins

The murine suppressive factor of allergy (SFA) has been purified from a T-cell hybridoma and found to consist of two functionally and biochemically distinct protein molecules. One protein (17 kDa) modulates the low-affinity Fc receptor for IgE on lymphocytes (i.e., CD23); it decreases the binding avidity of IgE to CD23-bearing B cells without affecting quantitative expression of CD23 and is thus designated epsilon-receptor-modulating protein. The second protein (30 kDa) suppresses IgE biosynthesis (i.e., SFA). This purified SFA suppresses interleukin 4-induced IgE and IgG1 synthesis by lipopolysaccharide-activated spleen cells but has no effect on other antibody isotypes; since the activity of SFA is not blocked by anti-interferon gamma monoclonal antibody, it is thus distinct from interferon gamma. The data presented indicate that epsilon-receptor-modulating protein and SFA are protein molecules that are involved in modulating the CD23 molecule and IgE antibody synthesis, respectively.

Differential stimulation of immune function by respiratory and contact chemical allergens

The nature of immune responses induced following topical exposure to 2,4-dinitrochlorobenzene (DNCB), a potent contact allergen which lacks the capacity to cause respiratory sensitization, and trimellitic anhydride (TMA), a respiratory allergen with comparatively weak skin-sensitizing potential, have been investigated. Exposure of BALB/c strain mice to concentrations of TMA and DNCB which resulted in equivalent levels of activation (cell proliferation) in lymph nodes draining the site of application (50% TMA and 1% DNCB) induced comparable levels of contact sensitization and IgG anti-hapten antibody production. However, under these conditions, exposure only to TMA resulted in an elevation of serum IgE. Furthermore, while TMA induced IgG2b rather than IgG2a antibody the reverse pattern was observed with DNCB. These data demonstrate that TMA and DNCB elicit qualitatively different immune responses which are consistent with their potential to cause respiratory and contact allergy, respectively. The possibility that the responses induced by these chemicals reflect a differential stimulation of T-helper cell subsets (Th1 and Th2) is discussed.

Anti-interferon gamma treatment blocks the ability of glutaraldehyde-polymerized allergens to inhibit specific IgE responses

The lymphokines interleukin 4 and interferon gamma (IFN-gamma) have been shown to play an important role in regulation of polyclonal immunoglobulin E (IgE) and IgG2a responses in vitro and in vivo. We demonstrate here that treatment with chemically modified ovalbumin (OA) results in long-lived, 97-99% inhibition of allergen-specific murine IgE responses and 10(3)-10(4)-fold increases in anti-OA IgG2a. Responses to unrelated antigens are not affected. Treatment with unmodified OA under the same conditions fails to inhibit primary or secondary IgE responses or to increase IgG2a but does lead to pronounced increases in OA-specific IgG1 production. Glutaraldehyde-polymerized ovalbumin (OA-POL)-induced changes in IgE and IgG2a responses are abrogated by in vivo treatment with purified monoclonal anti-IFN-gamma antibody (XMG 1.2), a finding indicative of preferential IFN-gamma production upon exposure to chemically modified, but not native, allergen. The results suggest the possibility that the pattern of cytokine synthesis elicited after exposure to protein antigens, and the resulting immune response, may be dependent upon the form of antigen to which the individual is exposed and consequently may be subject to manipulation.

Distinctive humoral immune responses following anterior chamber and intravenous administration of soluble antigen. Evidence for active suppression of IgG2-secreting B lymphocytes

Inoculation of soluble antigen into the anterior chamber (AC) of the eyes of mice and rats induces a distinctive form of immune deviation known as anterior chamber-associated immune deviation (ACAID). Similarly, intravenous injections of soluble antigen induce immune deviation. In both instances, a selective impairment of delayed hypersensitivity (DH) is observed, whereas humoral immunity is said to be preserved. Recently, we noted that radiolabelled bovine serum albumin (BSA) was not eliminated in an immune fashion from the blood of animals pretreated with this antigen via AC and intravenous (i.v.) routes of inoculation. This was puzzling because the sera of these animals contained easily measurable anti-BSA antibodies. We have examined the characteristics of the anti-BSA humoral responses of mice following i.v. and AC inoculation of BSA in order to understand the reason for the lack of immune elimination. The results indicate that AC and i.v. recipients fail to eliminate antigen in an immune fashion because they produce insufficient amounts of complement-fixing (IgG2) antibodies, even though the other isotypes of immunoglobulins are well represented in the humoral anti-BSA response. The pattern of antibody isotype production, especially after boosting with BSA in complete Freund's adjuvant (CFA), implies that activation of IgG2-secreting, BSA-specific B cells is suppressed. Evidence is presented demonstrating this suppression to be antigen-specific and mediated by CD8+ T lymphocytes. These data are compatible with the hypothesis that interleukin-4 (IL-4)-secreting T helper (Th) cells are selectively activated in ACAID, whereas interferon-gamma (IFN-gamma)IL-2-secreting Th cells are actively suppressed.

Autoimmune reactions to heat-shock proteins in pristane-induced arthritis

The development of arthritis induced in mice by intraperitoneal injection of the non-antigenic mineral oil, 2,6,10,14-tetramethylpentadecane (pristane), was shown to depend on an intact immune response possibly to a heat-shock protein (hsp) in the synovium. Initial experiments suggested that some crucial event in the development of arthritis takes place early after pristane injection. First, irradiated pristane-treated mice failed to develop arthritis unless they were reconstituted with spleen cells from normal donors within 25 days of irradiation. Second, mice irradiated up to 50 days after pristane injection, but not later, did not develop arthritis. Evidence for the involvement of an immune response to heat-shock protein (hsp) comes from the finding that mice injected with mycobacterial 65-kDa hsp prior to pristane challenge had a reduced incidence of arthritis in contrast to animals pre-immunized with the E. coli hsp equivalent GroEL or with bovine serum albumin. Other experiments revealed that T cells from mice with gross morphologically defined arthritis proliferated strongly to hsp65 and to normal joint antigens, whereas T cells from animals treated with pristane which did not develop arthritis gave much smaller responses. Mice which developed arthritis also had elevated levels of anti-hsp65 IgG in comparison with non-arthritic animals. These findings strongly suggest that autoimmune reactions to an antigen which cross-reacts with hsp65 are generated in pristane-induced arthritis. It is considered that the autoimmune response is directed to a synovial antigen and that pre-immunization with hsp65 protects the animals from the development of pristane-induced arthritis by altering the specificity or quality of the immune response to this antigen.

Persistence of anti-donor allohelper T cells after neonatal induction of allotolerance in mice

BALB/c mice rendered tolerant to A/J alloantigens by neonatal injection of 10(8) (A/J X BALB/c)F1 spleen cells develop an autoimmune disease associated with a polyclonal activation of donor B cells. To study the mechanisms leading to donor B cell activation in tolerant mice, we prepared mixed lymphocyte cultures (MLC) between splenic T cells from neonatally injected mice and donor-type (A/J X BALB/c)F1 or third-party (C57BL/6 X BALB/c)F1 B cells. T cells from tolerized mice were unable to generate cytotoxic T lymphocytes, to proliferate or to secrete interleukin (IL)2 after stimulation with donor alloantigens in MLC. These T cell responses were present after MLC with third-party antigens, but were of lower intensity than those generated by control BALB/c T cells. In contrast, T cells from tolerized mice stimulated immunoglobulin production by donor-type (A/J X BALB/c)F1 B cells much more powerfully than T cells from control BALB/c mice. The stimulation of donor-type (A/J X BALB/c)F1 B cells was polyclonal, as attested by the levels of anti-hapten and anti-DNA antibodies in the MLC supernatants. IgM was the dominant isotype secreted in vitro, but IgG1 and IgG3 were also produced in significant amounts. Lysis experiments indicated that the T cells responsible for F1 B cell stimulation in MLC were CD4+ host T cells. These T helper cells were alloreactive since they did not stimulate syngeneic BALB/c B cells, and their effect on donor B cells was specifically blocked by anti-donor Ia monoclonal antibodies. Addition of anti-IL 4 monoclonal antibody to MLC between T cells from tolerant mice and (A/J X BALB/c)F1 B cells almost completely abolished the production of IgG1, but not that of IgM or IgG3. Taken together, these findings indicate that neonatal injection of alloantigens in BALB/c mice induces a state of dissociated tolerance, with unresponsiveness of anti-donor T cells secreting IL 2 on the one hand, and persistence of T cells responsible for B cell help and IL 4 secretion on the other hand.

Establishment of different T cell sublines using either interleukin 2 or interleukin 4 as growth factors

Purified protein derivative reactive T cell lines were established under identical conditions with the exception that different lymphokines, namely interleukin (IL) 2 and IL 4 were employed as growth factors. IL 2 favored the development of T cell lines (LNC.2) which upon activation by concanavalin A (Con A) secreted predominantly lymphokines characteristic of TH1 cells. By contrast, T cell lines established with the aid of IL 4 as growth factor (LNC.4) produced mainly lymphokines representative of TH2 cells. Apart from their pattern of lymphokine secretion LNC.2 and LNC.4 T cells were found to differ in their proliferative response to lymphokines and Con A. LNC.2 T cells proliferated only marginally in the presence of IL 4, Con A or a combination of Con A and IL 1. Furthermore, the IL 2-dependent proliferation of LNC.2 T cells was slightly but significantly diminished by IL 4. In contrast, LNC.4 T cells showed a substantial IL 4-induced proliferative response which was on the one hand synergistically enhanced by minimal amounts of IL 2 and, on the other hand, strongly inhibited by interferon-gamma. In addition, LNC.4 T cells displayed a strong proliferation when stimulated by low concentrations of Con A in the presence of IL 1 as co-stimulator.

Deficits in T helper cells after total lymphoid irradiation (TLI): reduced IL-2 secretion and normal IL-2 receptor expression in the mixed leukocyte reaction (MLR)

Spleen cells from BALB/c mice treated with total lymphoid irradiation (TLI) and from normal, unirradiated mice were compared in the mixed leukocyte reaction (MLR). Although the percentage of CD4+ cells in the spleen was close to normal, 4 to 6 weeks after TLI, the MLR of unfractionated spleen cells from irradiated mice was more than 10-fold lower than controls. A similar reduction was observed when purified CD4+ cells were used as responders in the MLR. Secretion of IL-2 by cells from irradiated mice was also about 10-fold lower than controls. However, the percentage of CD4+ and CD8+ cells which expressed IL-2 surface receptors during the MLR was similar using spleen cells from irradiated and control mice. Addition of an exogenous source of IL-2 restored the proliferative capacity of the irradiated cells and suggests that the lack of IL-2 secretion is the likely explanation of the marked deficit in the MLR of CD4+ spleen cells after TLI.