Antibody-dependent cellular cytotoxicity and natural killer cytotoxicity of peritoneal cells from nude mice to herpes simplex virus-infected cells

Nude BALB/c mice (athymic) were more susceptible to fatal herpes simplex virus (HSV) than normal BALB/c mice (P = 0.002). The peritoneal cells of nude mice mediated levels of antibody-dependent cellular cytotoxicity (ADCC) of equal or greater magnitude than cells from normal BALB/c, heterozygote nu/+, or C57BL/6 mice. Unstimulated natural killer cytotoxicity of peritoneal cells from nude mice was higher (P less than 0.05) than that mediated by cells from C57BL/6 mice. Nude mice failed to make anti-HSV ADCC antibody 6 to 14 days post HSV inoculation, at times when nu/+, BALB/c, and C57BL/6 mice produced antibody. Passive reconstitution of nude mice with high titer intraperitoneal anti-HSV immune globulin provided circulating anti-HSV ADCC antibody and significant protection against lethal HSV infection.     

Protection against murine neonatal herpes simplex virus infection by lymphokine-treated human leukocytes

One-week-old mice were protected against a uniformly lethal herpes simplex virus (HSV) infection by IL-2 alone, but especially by the addition of human mononuclear cells (MC) plus IL-2. The dose response of IL-2 was biphasic. The addition of MC from cord blood did not enhance IL-2-mediated survival. Because the effect of IL-2 alone, or IL-2 plus MC, was ablated by anti-IFN-gamma and human neonates have an IFN-gamma production defect, the protective effect of MC plus human IFN-gamma (HuIFN-gamma) was tested. MC from adults cultured for 5 days in HuIFN-gamma afforded protection. At least 1 x 10(6) HuIFN-gamma-treated MC were required with increasing survival to 1 x 10(7) MC. The effector cell activity was ablated by adherence, silica, L-leucine methyl ester treatment or treatment with Leu-M3 plus C (all macrophage markers), and OKT4 plus C treatment (CD4 marker). Use of Leu-11, Leu-7, OKT3, or OKT8 plus C did not inhibit protection and excluded NK or T cell participation. In addition to survival, the ability to produce anti-HSV antibody was reconstituted. For the first time protection was afforded by human cord blood MC after treatment with HuIFN in vitro. We have identified an IFN-gamma-driven protection system against murine neonatal HSV infection mediated by human adult- or cord blood-derived CD4-positive macrophages. Protection is associated with enhanced effector cell function and reconstitution of the neonatal antibody production defect.     

Protection of neonatal mice against herpes simplex virus infection: probable in vivo antibody-dependent cellular cytotoxicity

Infant mice are extremely susceptible to fatal Herpes simplex virus (HSV) infection. They are unable to produce antibody to HSV, and their leukocytes cannot mediate antibody-dependent cellular cytotoxicity (ADCC) to HSV-infected cells. In order to avoid H-2-dependent effector mechanisms and instead analyze possible in vivo ADCC, a murine model employing adoptive transfer of antibody and human leukocytes was developed. Administration of either human immune globulin or leukocytes i.p. from HSV immune or nonimmune humans could not protect infant C57BL/6 mice from fatal HSV infection. In contrast, a combination of a subneutralizing dilution of globulin and leukocytes from nonimmune or immune human donors, given one day before inoculation, was highly protective against lethal HSV infection. The cells involved included lymphocytes or monocyte-macrophages. At least 5 X 10(6) viable leukocytes (or 1 X 10(6) monocyte-macrophages) and immune serum globulin concentrations as low as 10(-8) were protective. Infected cell monolayer adsorption and DEAE column fractionation demonstrated that the protection by globulin was due to specific antiviral IgG antibody. Protection was n ot seen in animals receiving virus before immune transfer. Protection did not involve synergistic viral neutralization by antibody and cells, as shown by in vitro experiments. Animals receiving globulin and cells, unlike normal infant mice, had circulating antiviral antibody and peritoneal leukocytes able to mediate ADCC to HSV-infected cells. This is the first in vivo evidence for the role of human ADCC. This model also allows for the in vivo evaluation of the ability of cells from immunocompromised humans to curb viral infection.     

The genetic deficiency of leukocyte surface glycoprotein Mac-1, LFA-1, p150,95 in humans is associated with defective antibody-dependent cellular cytotoxicity in vitro and defective protection against herpes simplex virus infection in vivo

The role of the Mac-1, LFA-1, p150,95 leukocyte glycoprotein family in mediating antiviral host defense was investigated by utilizing mononuclear cells (MC) obtained from eight patients with a genetic deficiency of Mac-1, LFA-1, and p150,95, and normal MC incubated with subunit-specific monoclonal antibodies (MAb) directed against these glycoproteins. As shown with an in vitro chromium-release cytotoxicity assay to herpes simplex virus (HSV)-infected Chang liver target cells, MC of these patients with the severe phenotype or normal MC preincubated with a combination of MAb against Mac-1 glycoprotein subunits were deficient in antibody-dependent cellular cytotoxicity (ADCC). When used individually, MAb directed at LFA-1-alpha or -beta also inhibited ADCC and natural killer cytotoxicity (NKC). In a single cell agarose assay, MC of Mac-1-deficient patients formed fewer effector-target cell conjugates in the presence of specific anti-HSV antibody. To investigate the in vitro contributions of these glycoproteins to cytotoxic host defense mechanisms, two in vivo adoptive transfer models were explored in which neonatal mice are protected against a lethal HSV challenge by normal human MC plus anti-HSV antibody (in vivo ADCC) or human interferon-alpha (NKC stimulated in vivo). In each model, MC from patients with "severe" or "moderate" phenotypes of Mac-1 deficiency, or normal MC incubated with a combination of anti-LFA-alpha, Mac-1-alpha, p150,95-alpha plus -beta MAb failed to protect neonatal mice against lethal HSV infection. These studies further indicate requirements for adhesion-dependent mechanisms in the mediation of MC-ADCC, and suggest that Mac-1-dependent cellular adhesive properties are necessary for normal cytotoxic functions in vivo in experimental models of human ADCC or interferon-stimulated NKC. These findings, in addition to the recognized occurrence of severe or even lethal viral infections in some Mac-1-deficient patients, suggest that glycoproteins of the Mac-1 family may be important determinants of antiviral host defense.     

Inhibition of antibody-dependent cellular cytotoxicity by autologous lymph node cells.

A population of lymph node cells that lack the usual T, B, or K cell markers was found to inhibit autologous spleen cells from mediating antibody-dependent cellular cytotoxicity (ADCC) to antibody-coated chicken erythrocytes. Inhibitor cells were not susceptible to treatment with anti-Thy 1.2 or anti-Ig and C; they did not adhere to Sephadex G-10, to nylon wool, or to monolayers of sheep erythrocytes (E) or erythrocytes plus 7S antibody (EA). After a brief (4-min) exposure to 45 degrees C, the ability to inhibit was lost whereas other cellular responses remained intact. ADCC mediated by nonadherent splenic effector cells (presumptive K cells) was highly susceptible to inhibition. Possible mechanisms for and implications of lymphocyte-mediated inhibition of ADCC are discussed.     

Suppression of antigen-specific interleukin 2 production in the MRL/MpJ-lpr/lpr mouse

Several murine strains with spontaneously occurring systemic lupus erythematosus-like disease demonstrate defects in immunoregulation. The MRL/MpJ-lpr/lpr (MRL-1) strain develops a severe age-progressive defect in interleukin 2 (IL 2) production in response to mitogen or antigen. In this study, we demonstrate in vitro the presence of suppressor cells in the lymph nodes of naive mice of the MRL background. Suppression by MRL-1 lymph node cells was partially reversed by treatment with anti-Lyt-1.2 monoclonal antibody and complement and was moderately radiosensitive. Suppression by lymph node cells from the congenic MRL/MpJ-+/+ (MRL-+) mouse was somewhat more resistant to treatment with anti-Lyt-1.2 and complement, or radiation. Lymph node cells from the H-2-syngeneic mouse strain, C3H/HeJ, failed to suppress. Thus, lymph nodes from mice of the MRL background contain cells capable of suppressing in vitro IL 2 responses. We next performed cell transfers to determine whether suppressor cells contribute in vivo to the IL 2 defect. Lymph node cells, but not spleen cells, from MRL-1 mice by 5 to 6 mo of age suppressed antigen-specific IL 2, CTL, and DTH responses when transferred into young MRL-+ recipients. Transfer of identical numbers of lymph node cells from age-matched MRL-+ mice failed to suppress IL 2 production. Transfer of suppression was sensitive to treatment with monoclonal anti-Lyt-2.1 and complement, and to 250 rad of radiation. Thus, this study suggests a role for active suppression of IL 2 production in the establishment of the IL 2 defect in the MRL-1 mouse. Further, suppression may involve phenotypically distinct T lymphocyte subpopulations.     

Bone marrow transplantation across major histocompatability barriers in mice. III. Treatment of donor grafts with monoclonal antibodies directed against Lyt determinants

We studied the effect of eliminating T cells from donor grafts of mice in a system in which bone marrow was transplanted across major histocompatibility barriers. BALB/c bone marrow (added as a source of hematopoietic stem cells) combined with equal volumes of spleen cells (added as a source of GVHD-promoting cells) was pretreated in vitro with monoclonal anti-Lyt-1.2 or Lyt-2.2 plus absorbed rabbit complement before injection into C57BL/6 total-body-irradiated recipients. Functional activity of anti-Lyt monoclonal antibodies was determined in CML assay. Treatment with anti Lyt-1.2 plus C did not have any anti-stem cell activity, as measured by CFU-S assay, and protected recipients from the onset of lethal GVHD. Treatment with Lyt-2.2 plus C also did not reduce CFU-S; however, mice receiving treated marrow did develop GVHD and were all dead by 2 mo, as were untreated control mice. Surviving "anti-Lyt-1.2 + C chimeras" demonstrated a high percentage of donor mononuclear cells in their peripheral blood. Similar results were obtained when C3H/HeN donor BMS was treated with monoclonal anti-Lyt-1.1 plus C and injected into C57BL/6 recipients. These findings show that monoclonal antibodies directed against determinants unrelated to Thy-1 can eliminate T cells in the presence of C and successfully protect transplanted mice from lethal GVHD. They also suggest that these anti-Lyt antibodies may be useful tools in determining subpopulations of T cells that contribute to the development of GVHD.     

Dual regulation of resistance against Toxoplasma gondii infection by Lyt-2+ and Lyt-1+, L3T4+ T cells in mice

Studies were performed to attempt to define the T cell subset responsible for resistance to Toxoplasma gondii. A temperature-sensitive mutant (ts-4) strain of T. gondii was used for immunization because it causes infection but does not persist in the host. Immunization with this strain induced marked resistance against lethal challenge infection with virulent strains of T. gondii in mice. The resistance could be transferred to normal recipient mice by i.v. injection of spleen cells from ts-4-immunized mice. Marked inhibition of cyst formation in the recipient mice was also noted. The protective activity of immune spleen cells was removed by pretreatment of the spleen cells with anti-Thy-1.2 and C, indicating that T cells are responsible for the observed protection. Pretreatment of immune spleen cells with anti-Lyt-2.2 and C completely ablated their protective effect; pretreatment with anti-Lyt-1.2 or anti-L3T4 and C had lesser effects on their ability to transfer resistance. The effect of anti-Lyt-1.2 was the same as that obtained with anti-L3T4. This suggested that one T cell subset that is partially responsible for protection has both Lyt-1.2 and L3T4 markers on the cell surface. These results indicate that there are substantial roles for both the Lyt-2+ and Lyt-1+, L3T4 T cell subsets in dual regulation of resistance against toxoplasma infection and that Lyt-2+ T cells are the principal mediator of the resistance.     

Mycoplasma pulmonis infection augments natural killer cell activity in mice

The goal of this study was to determine if experimental Mycoplasma pulmonis infection augmented splenic natural killer (NK) cell activity in mice. A 4 hour 51Cr-release in vitro assay using YAC-1 tumor target cells was employed to measure splenic NK cell activity in C57BL/6J mice infected intraperitoneally with M. pulmonis and in uninfected controls. Transient augmentation of the NK cells was observed, peaking at day 3 postinoculation (PI) and gradually returning to normal levels by day 10 PI. Selective depletion studies showed that the cells responsible for killing target cells were NK cells. They were nonadherent to nylon wool, not susceptible to Thy-1.2 antibody and susceptible to asialo GM1 ganglioside antibody. Inadvertent augmentation of the NK cell system due to M. pulmonis infection may complicate the interpretation of research data, especially in immunology and cancer studies.     

Nuclear disintegration of target cells by killer B lymphocytes from tumor-bearing mice

Normal murine B lymphocytes are not known to be effectors of the Fc receptor-mediated, antibody-dependent cellular cytotoxicity (ADCC). In contrast, we report here that highly purified splenic B cells from mammary tumor-bearing mice develop the potential of lysing antibody-coated target cells. These lymphocytes are characterized by being G-10 nonadherent, nylon wool adherent, sIg+, FcR+, Thy 1.2-, asialo GM1-, and the immunoglobulin heavy-chain genes of both chromosomes are rearranged. The lytic reaction is characterized by a noninterdigitating binding and by the appearance of endocytotic vesicles in the target cells. Nuclear disintegration occurs 18 h after initial effector-target cell conjugate formation. At such time, only minor cytoplasmic membrane alterations are evident. The emergence of killer B cells in tumor-bearing hosts indicates that all lymphoreticular cell types bearing Fc receptors are capable of mediating ADCC.     

Suppressive effect of nonviable Mycobacterium paratuberculosis on the delayed-type hypersensitivity reaction to sheep erythrocytes in mice.

The effect of nonviable Mycobacterium paratuberculosis on the delayed-type hypersensitivity reaction to sheep erythrocytes (SRBC) in mice was evaluated by means of delayed-type footpad swelling. Intraperitoneal (i.p.) injection with nonviable M. paratuberculosis into mice from 28 days before to 1 day after immunization with SRBC resulted in a significant suppression of foot-pad swelling to SRBC. The suppressive effect could be transferred by i.p. injection of spleen cells or peritoneal exudate cells from mice which had been pre-treated with nonviable M. paratuberculosis into non-treated recipient mice. The suppressive effect of spleen cells was retained even after passing them through a nylon wool column. The suppressive effect of spleen cells was abolished by treatment with anti-Thy 1.2 monoclonal antibody plus complement or anti-Lyt 2.2 monoclonal antibody plus complement. However, treatment of spleen cells with anti-mouse gamma globulin antiserum plus complement or anti-Lyt 1.2 monoclonal antibody plus complement did not affect the suppressive effect of spleen cells. The suppression of footpad swelling to SRBC induced by pre-treatment with nonviable M. paratuberculosis could be reversed by i.p. administration of cyclophosphamide. Serum antibody response to SRBC in mice was not affected by pre-treatment with nonviable M. paratuberculosis. These findings indicate that T cells appear to be involved in the suppression of delayed-type hypersensitivity reaction to SRBC in mice by pre-treatment with nonviable M. paratuberculosis.     

Cell contact-mediated macrophage activation for antileishmanial defense. II. Identification of effector cell phenotype and genetic restriction

Host defense in cutaneous leishmaniasis, due to Leishmania tropica, is largely--if not exclusively--cell mediated. We observed in vitro that draining lymph node lymphocytes from L. tropica-infected C57BL/6 mice activate L. tropica-infected macrophages to kill the intracellular parasites (leishmanicidal effect). Because direct cell contact between lymphocytes and infected macrophages is required to achieve a maximum leishmanicidal effect, this effect cannot be attributed solely to lymphokines. Furthermore, because effector lymphocytes induced no detectable damage to infected macrophages, the effect also differs from conventional lymphocyte-mediated cytotoxicity. The present study identifies the phenotype of the effector lymphocyte and assesses the genetic restriction of the lymphocyte-macrophage interaction. Nylon wool column-enriched T lymphocytes from infected mice activate macrophages for antileishmanial effects; treatment of lymphocytes with anti-Thy-1.2 antibody plus complement abolishes this capacity. Furthermore, treatment with anti-Lyt-1 antibody plus complement (but not with anti-Lyt-2 plus complement) likewise abolishes the effector capacity of the lymphocytes. Parallel studies reveal that the percentage of Lyt-1+2- cells present in draining lymph nodes increases during the course of infection and reaches a peak with the onset of spontaneous resolution of the infection. Syngeneic, but not allogeneic, combinations of lymphocytes and infected macrophages result in macrophage activation. Furthermore, treatment of cells with appropriate anti-Ia monoclonal antibody abrogates the antileishmanial effects. These results indicate that Lyt-1+2- lymphocytes obtained from mice with spontaneously healing L. tropica infections can exert antileishmanial effects in vitro. This effect is genetically restricted--most likely to the I region of the MHC--and requires direct cell contact. The temporal relationship between the appearance of these effector lymphocytes in mice and the onset of disease resolution argues that they may also exert these antileishmanial effects in vivo.     

Interleukin 2 production by lymphoid cells from congenitally athymic (nu/nu) mice

The ability of lymphoid cells from congenitally athymic (nu/nu) mice to produce interleukin 2 (IL 2) was investigated. Spleen or lymph node cells (superficial or mesenteric) from nude mice on an N:NIH(S)II or BALB/c genetic background were stimulated with concanavalin A (Con A) or with irradiated allogeneic (DBA/2) spleen cells that had been depleted of T cells by treatment with monoclonal anti-Thy-1.2 antibody plus complement. After 24 hr, supernatants were harvested and assayed for their ability to support the proliferation of a cloned IL 2-dependent cytolytic T cell line. With this quantitative microassay, IL 2 production was not detectable in spleen and lymph nodes of 6-wk-old N:NIH(S)II nude mice; however, by 12 mo of age, IL 2 production increased more than 100-fold to reach levels comparable to control (nu/+) animals. Con A was more potent than alloantigen in the induction of IL 2 in either nude or control (nu/+) animals. Furthermore, differences in the genetic background of nude mice resulted in corresponding differences in both numbers of T cells (defined by monoclonal anti-Thy-1 antibody) and IL 2 production. By using negative selection with monoclonal antibodies plus complement, IL 2 production in aged nude mice was shown to depend upon a subpopulation of cells that expressed Thy-1 but not Lyt-2. These data thus demonstrate that a subpopulation of IL 2-producing cells with a Thy-1+ Lyt-2- surface phenotype can develop in the apparent absence of thymic influence.     

Enterically induced regulation of systemic immune responses. II. Suppression of proliferating T cells by an Lyt-1+, 2- T effector cell

Peripheral lymph node cells from C3H mice that were fed and injected with bovine serum albumin (REG cells) demonstrate an impaired proliferative response to antigenic stimulation in vitro compared to cells from mice only injected with BSA. To determine whether suppressor cells contributed to this enterically induced impairment of systemic T cell responses, REG cells were pretreated with various monoclonal antibodies and complement (C), and were then co-cultured with antigen-reactive indicator T cells (IND) from parenterally immunized mice. Proliferation of IND cells [( 3H]thymidine uptake) was suppressed only if REG cells were treated with anti-Lyt-2 and C before co-culture. The ability of anti-Lyt-1 plus anti-Lyt-2 and C treatment to abrogate suppression suggested that the suppressor effect was due to an Lyt-1+, 2- REG cell. Suppression was independent of Lyt-2+ IND cells, and was observed at different antigen concentrations, cultivation times, and cell densities. The cells responsible for suppressor activity were radiosensitive, nylon wool nonadherent, and antigen specific. These data suggest that an Lyt-1+, 2- T cell could be an important component in mediating enterically induced regulation of systemic T cell responses.     

Interleukin 2 deficiency in murine Leishmaniasis donovani and its relationship to depressed spleen cell responses to phytohemagglutinin

This study examined the kinetics and mechanisms of depressed spleen cell responses to phytohemagglutinin (PHA) that occur during Leishmania donovani infection of BALB/c mice. In co-culture experiments, neither spleen cells from infected animals nor parasite-infected macrophages suppressed PHA responses of normal spleen cells. In addition, parasite-mediated suppression of PHA-stimulated spleen cell proliferation could not be demonstrated. Mice with 2 wk of infection did manifest an impairment in spleen cell production of interleukin 2 (IL 2) and by 8 wk IL 2 activity in supernatants from these cells was reduced by approximately 95%. This finding was not explained by an alteration in the kinetics of IL 2 production. Furthermore, diminished IL 2 activity in supernatants of PHA-activated spleen cells from infected animals was not caused by suppressive factors in these fluids as shown by their inability to suppress IL 2 stimulation of IL 2-dependent T cells. When spleen cells from mice with 8 wk of infection were cultured with PHA and supplemented with exogenous IL 2, there was an approximately 48% increase in mitogenesis. These data indicate that abnormal PHA-induced spleen cell activation in BALB/c mice with L. donovani infection is associated with impaired production of IL 2. In addition, the observation that supplementation of spleen cells from infected mice with IL 2 resulted in partial reconstitution of the PHA response is consistent with a defect in IL 2 responsiveness.     

Lymphokine-activated tumor inhibition in vivo. I. The local administration of interleukin 2 triggers nonreactive lymphocytes from tumor-bearing mice to inhibit tumor growth

CE-2 is a chemically induced tumor of low immunogenicity in syngeneic BALB/c mice. Nylon wool columns eluting lymphocytes from the spleen of mice bearing clinically evident (5-mm mean diameter) CE-2 tumors (CE-2 TB lymphocytes) do not react with CE-2 cells in vitro, nor are they able to affect their growth in vivo in a Winn-type neutralization assay at 5:1 lymphocyte:tumor cell ratio. However, they become able to inhibit CE-2 tumor growth when 20 U of interleukin 2 (IL 2) in 0.4 ml are injected daily for 10 days at the challenge site. In contrast, mice injected with CE-2 cells and IL 2 only display tumor takes and growth that are not significantly different from those in controls challenged with CE-2 cells alone. This lymphokine-activated tumor inhibition (LATI) is not a peculiarity of the CE-2 tumor-host combination, because different tumors can be inhibited in this way and various TB lymphocytes can initiate it. In these experiments, IL 2-rich 25,000 to 30,000 m.w. fractions were obtained routinely from the culture supernatants of a clone of EL-4 thymoma stimulated with phorbol myristic acetate. Equally active IL 2-rich preparations were obtained from rat spleen cells stimulated with concanavalin A, or from MLA 144 gibbon lymphosarcoma spontaneously releasing IL 2. Treatment of CE-2 TB lymphocytes with various antibody and C, with 2000 rad gamma-irradiation, or fractionation on Percoll density gradients suggested that radioresistant functions of Thy-1.2+, Lyt-1.2+, Lyt-2.2- and of asialo GM1+ cells are independently involved in LATI induction. These lymphocytes inhibit tumor growth by recruiting the radiosensitive effector mechanisms of the recipient mice required for ultimate tumor destruction. CE-2 tumor inhibition by LATI leaves a specific delayed-type hypersensitivity and an immunologic memory, resulting in rejection of a second lethal CE-2 challenge in a significant number of mice.     

Autoimmune thyroiditis induced in mice depleted of particular T cell subsets. I. Requirement of Lyt-1 dull L3T4 bright normal T cells for the induction of thyroiditis

T cell-depleted C3H/He or (C57BL/6xC3H/He)F1 (B6C3F1) mice were prepared by adult thymectomy and injection of antithymocyte serum, followed 3 wk later by lethal x-irradiation and bone marrow reconstitution. When these T cell-depleted mice were not injected or injected i.v. with normal spleen and lymph node cells treated with either anti-Thy-1, -L3T4 or -Lyt-2 antibody plus C or C alone, none of the groups of mice developed thyroiditis. In contrast, the adoptive transfer of normal cells treated with anti-Lyt-1 plus C resulted in high incidence of the production of antithyroglobulin antibody and the induction of typical thyroiditis lesion. The thyroid was the sole organ involved, because neither typical inflammatory lesion in other organs nor autoantibody such as anti-DNA antibody was detected in mice that exhibited thyroiditis. Analyses of surface phenotypes of cells required for inducing thyroiditis by the adoptive transfer revealed that an appreciable percentage of Lyt-1 dull T cells remained after the treatment of normal lymphoid cells with anti-Lyt-1 plus C. Almost all of these Lyt-1 dull T cells expressed magnitudes of L3T4 or Lyt-2 Ag comparable to those detected on Lyt-1 bright T cells. More important, the induction of thyroiditis was almost completely prevented by either in vitro or in vivo elimination of Lyt-1 dull L3T4+(bright) but not of Lyt-1 dull Lyt-2+(bright) T cells. These results indicate that Lyt-1 dull L3T4+ T cells existing in normal healthy individuals have potential to induce typical thyroiditis which is associated with the production of antithyroglobulin autoantibody, and that the activation and/or function of this T cell subset is regulated by the Lyt-1 bright T cell population coexisting in normal lymphoid cell population.     

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.     

Heterologous antibody responses in mice with chronic T. cruzi infection: depressed T helper function restored with supernatants containing interleukin 2

Antibody production to sheep erythrocytes (SRBC) or hapten-conjugated SRBC (TNP-SRBC) was studied in mice with chronic Trypanosoma cruzi infections. Studies in vivo demonstrated that both IgM and IgG anti-SRBC responses were suppressed during chronic infection. Secondary IgG responses were suppressed regardless of whether the primary immunization was given before or after infection. The ability of cells from infected mice to provide help for antibody production was examined in vitro. Anti-SRBC responses were restored to cultures of whole spleen cells from infected mice by the addition of interleukin 2 (IL 2)-rich supernatants, indicating that these cells were capable of antibody production when sufficient help was provided. T cells from SRBC-primed infected mice were unable to provide significant help to normal B cell/M phi cultures for in vitro anti-TNP or anti-SRBC responses. The percentages of Thy-1+, Lyt-1+, and Lyt-2+ spleen cells were not significantly different between normal and infected mice. Anti-TNP and anti-SRBC responses were restored to cultures that contained T cells from infected mice and normal B cell/M phi by the addition of IL 2-rich spleen cell supernatants. The suppression of in vitro antibody responses in mice with chronic T. cruzi infections was associated with a lack of T cell help, which was provided by exogenous spleen cell supernatant.     

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.