Search

In different murine systems, delayed-type hypersensitivity (DTH) swelling responses at 24–48 hr after antigen challenge were preceeded by an early 2-hr swelling response. The 24-hr DTH response is thought to depend on this early (DTH-initiating) hypersensitivity response. In this paper we show that in the syngeneic DBA/2-SL2 routine turnout system only an early 2-hr swelling response can be evoked. This early hypersensitivity response was tumour specific and serotonin dependent. The early hypersensitivity response in contact hypersensitivity has been ascribed to antigen-specific T-cell factors. To test whether similar T-cell factors were involved in the early hypersensitivity response in this syngencic turnout system, we have transferred lymph node, spleen lymphocytes and scram from immunized mice into naive recipients. The serum was fractionated in two fractions, a 50,000–80,000 MW fraction, and a 120,000–190,000 MW fraction. In recipients of lymphocytes, total serum and the 50,000–80,000 MW fraction of the serum, an early hypersensitivity response can be evoked. So, these data suggest the involvement of specific T-cell factors in the development of an early hypersensitivity response against syngeneic tumour cells. Despite the development of an early (DTH initiating) hypersensitivity swelling response these immunized animals cannot develop a classical 24-hr swelling response. This absence of the 24-hr response in the presence of the 2-hr response is discussed in relation to the frequently observed immune suppression in tumour-bearing mice. [ABSTRACT FROM AUTHOR]

Previous work from this laboratory has shown that preimmunization of syngeneic hosts with Rous sarcoma virus (RSV)-transformed cells elicits a strong immune response against the growth of transplantable RSV sarcomas, mediated by T lymphocytes expressing the surface phenotype of helper cell precursors (Prat, Di Renzo & Comoglio, 1983). This paper shows that anti-tumour immunity may be elicited in tumour-bearing animals by triggering an experimentally pre-amplified T-helper cell population at the site of tumour growth. Mice were treated with cyclophosphamide (which inactivates suppressor T cells) followed by skin sensitization to trinitrochlorobenzene (TNCB) according to a protocol that has been shown to induce an appreciably amplified generation of trinitrophenyl (TNP)-reactive helper T cells (Fujiwara et al., 1984). Five weeks after TNCB painting, mice were transplanted s.c. with a lethal dose of RSV-induced syngeneic sarcoma cells; the injection at the tumour site of TNCB induced the regression of the tumour in mice in which the TNP-helper cell population has been amplified, but not in controls, including those injected with a non-related hapten or sensitized to TNCB without inactivation of suppressors. [ABSTRACT FROM AUTHOR]

This paper uses B-lymphocyte cloning methods to quantify the effects of anti-μ chain antibody on immature and mature B cells. Nude mouse spleen lymphocytes were incubated with various concentrations of sheep anti-mouse μ chain antibody for times varying from 10 min to 24 h. They were then washed and plated in the agar B-cell colony formation assay. Five to six days later, control B cells had developed into colonies with a plating efficiency of about 5%. B cells from newborn mice pretreated with anti-μ yielded fewer colonies. Remarkably low concentrations sufficed to inhibit subsequent mitogenesis. For example, 3 μg/ml acting for 1 h or 0.1 μg/ml acting for 24 h gave > 50% inhibition. Adult B cells were about thirty-fold more resistant to negative signalling. Immature cells became more profoundly inhibited as anti-μ treatment was prolonged. Anti-Ia or anti-H2 antibodies, in the absence of complement, did not deliver a negative signal. Anti-μ pretreatment also reduced the capacity of immature B cells to form clones of anti-hapten antibody-forming cells in a liquid microculture system where the triggering stimulus was a T-cell independent antigen. Mature 'T-independent' B cells were not inhibited. Populations of hapten-specific B cells prepared by the hapten-gelatin method were investigated in the agar cloning system. Pretreatment of immature cells with anti-μ reduced their capacity to form colonies, this subpopulation of cells behaving like unfractionated B cells. Furthermore, hapten--HGG delivered a negative signal also. Mature hapten-specific cells or unfractionated immature spleen cells formed normal numbers of colonies following hapten HGG treatment. Overall, the studies support the view that anti-μ antibody and hapten--HGG deliver strong negative signals to immature but not mature cells with appropriate receptors. The value of anti-μ as a model, universal tolerogen was supported. Fluorescence-activated cell sorter (FACS) analysis was performed to study the relationships between functional inhibition and Ig receptor modulation. We confirmed that the IgM receptors of immature B cells are more readily modulated by anti-μ antibody than those of mature cells. Furthermore, the receptor regeneration could be partially inhibited amongst immature but not mature B cells. There was not a close quantitative relationship between the degree of modulation and the degree of functional inhibition. The results did not support the view that irreversible receptor modulation as such was the cause of functional inhibition. [ABSTRACT FROM AUTHOR]

Lymph node and spleen cells from normal mice were cultured for 3 days with polyoma virus-induced tumour, Ehrlich's ascites turnout or leukaemia L 1210 cells. This resulted in in vitro immunization of the lymphocytes, which were then transferred to irradiated target cells labelled with 51Cr. Normal, i.e. non-immune thioglycollate-stimulated peritoneal macrophages were also added to some tubes. Non-immune macrophages mixed with immunized lymphocytes showed a significantly increased ability to destroy tumour ceils as compared with macrophages in the absence of immunized lymphocytes. The immunized lymphocytes were almost entirely inactive alone. When the number of macrophages was kept constant the cytotoxicity was dependent on the number of viable immunized lymphocytes placed on the target cells. Immunized lymphocytes, in the presence of macrophages, only exhibited strong killing of the target cells against which they had been immunized; some lysis of ‘bystander’ cells was, however, seen provided specific target cells were present. Macrophage monolayers exposed to immunized lymphocytes upon contact with specific antigen became ‘armed’ and showed a significant cytotoxicity for specific target cells. When immunized lymphocytes and normal macrophages were treated with actinomycin D and puromycin, cytotoxicity was inhibited in the immunized lymphocytes but not in the macrophages. The possible mechanism of normal macrophage cooperation with immunized lymphocytes in the cytotoxic killing reaction is discussed. Results presented in this paper favour the view that immunologically specific cytophilic factor (presumptive cytophilic antibody) is involved in the macrophage-mediated cytotoxicity in the system studied. [ABSTRACT FROM AUTHOR]

To clarify the effect of secretory IgA (s IgA) deficiency on gut homeostasis, we examined intraepithelial lymphocytes ( IELs) in the small intestine ( SI) of polymeric immunoglobulin receptor-deficient ( pIgR−/−) mice. The p IgR−/− mice exhibited the accumulation of CD8 αβ+ T-cell receptor ( TCR)- αβ+ IELs ( CD8 αβ+ αβ- IELs) after weaning, but no increase of CD8 αβ+ γδ- IELs was detected in pIgR−/− TCR- β−/− mice compared with pIgR+/+ TCR- β−/− mice. When 5-bromo-2′-deoxyuridine (BrdU) was given for 14 days, the proportion of BrdU-labelled cells in SI- IELs was not different between pIgR+/+ mice and pIgR−/− mice. However, the proportion of BrdU-labelled CD8 αβ+- IELs became higher in pIgR−/− mice than pIgR+/+ mice 10 days after discontinuing BrdU-labelling. Intravenously transferred splenic T cells migrated into the intraepithelial compartments of pIgR+/+ TCR- β−/− mice and pIgR−/− TCR- β−/− mice to a similar extent. In contrast, in the case of injection of immature bone marrow cells, CD8 αβ+ αβ- IELs increased much more in the SI of pIgR−/− TCR- β−/− mice than pIgR+/+ TCR- β−/− mice 8 weeks after the transfer. αβ- IELs from pIgR−/− mice could produce more interferon- γ and interleukin-17 than those of pIgR+/+ mice, and intestinal permeability tended to increase in the SI of pIgR−/− mice with aging. Taken together, these results indicate that activated CD8 αβ+ αβ- IELs preferentially accumulate in pIgR−/− mice through the enhanced differentiation of immature haematopoietic precursor cells, which may subsequently result in the disruption of epithelial integrity. [ABSTRACT FROM AUTHOR]

Basophils are known to modulate the phenotype of CD4+ T cells and to enhance T helper type 2 responses in vitro and in vivo. In this study, we demonstrate that murine basophils inhibit proliferation of CD4+ T cells in autologous and allogeneic mixed lymphocyte reactions. The inhibition is independent of Fas and MHC class II, but dependent on activation of basophils with subsequent release of interleukin-4 ( IL-4) and IL-6. The inhibitory effect of basophils on T-cell proliferation can be blocked with antibodies against IL-4 and IL-6 and is absent in IL-4/ IL-6 double-deficient mice. In addition, we show that basophils and IL-4 have beneficial effects on disease activity in a murine model of acute graft-versus-host disease (Gv HD). When basophils were depleted with the antibody MAR-1 before induction of Gv HD, weight loss, Gv HD score, mortality and plasma tumour necrosis factor levels were increased while injection of IL-4 improved Gv HD. Basophil-depleted mice with Gv HD also have increased numbers of CD4+ T cells in the mesenteric lymph nodes. Our data show for the first time that basophils suppress autologous and allogeneic CD4+ T-cell proliferation in an IL-4-dependent manner. [ABSTRACT FROM AUTHOR]

C1q deficiency has been shown to accelerate spontaneous autoimmunity in mice. We studied the time course of activation of monocytes and lymphocytes in autoimmune and non-autoimmune mice in the presence or absence of C1q as a disease accelerator. Autoimmune MRL\Mp. C1qa −\− and non-autoimmune C57BL\6. C1qa −\− mice were analysed at various time points between 6 and 33 weeks of age and compared to strain- and age-matched C1q-sufficient controls. Splenic and peritoneal leucocytes were analysed by flow cytometry and plasma levels of immunoglobulin M (IgM), total IgG, IgG subclasses and IgM autoantibodies were measured. Both C1q-deficient strains had significantly more splenic monocytes than their controls at all time points analysed. In addition, MRL\Mp. C1qa −\− but not C57BL/6. C1qa −\− mice developed splenic hypercellularity starting at about 12–17 weeks old, had signs of accelerated CD4+ T-cell activation and showed a marked increase in splenic plasma cells and total serum IgM levels from about 22 weeks of age. The accelerated CD4+ T-cell activation was not due to a direct inhibitory effect of C1q on T cells. These data show that C1q deficiency causes splenic monocytosis together with accelerated T-cell activation in an autoimmune-prone mouse strain. [ABSTRACT FROM AUTHOR]

In an attempt to identify urodele amphibian lymphocyte subpopulations by their surface markers, we prepared hybridomas from BALB/c mice spleen immunized with axolotl (Ambystoma mexicanum) blood and splenic leucocytes and purified immunoglobulins. Sixty-five hybridomas were selected and subsequently subcloned. Among numerous monoclonal antibodies (mAbs) thus obtained, four mAbs were extensively characterized by immunoblotting, single and double fluorescence and immunohistology. MAb 34.38.6 recognizes polypeptides between 65,000 and 72,000 MW and labels in immunofluorescence nearly all thymocytes, 60-63% splenic lymphocytes of normal animals but only 9% splenic lymphocytes in thymectomized animals. MAb 19.14.2 reacts with a 98,000 MW protein and labels a restricted lymphocyte population in thymus (52-77%) and spleen (20-25%). The immunohistological study demonstrates that 34.38.6 and 19.1 4.2 label most thymocytes and a large proportion of spleen leucocytes including lymphocytes, granulocytes and macrophages. In addition, 19.14.2 labels some large interdigitating cells in thymic epithelial areas and splenic cords. MAbs 33.45.1 and 33.101.2, respectively, recognize heavy (72,000-88,000 MW) and light (20,000-27,000 MW) axolotl immunoglobulin chains. They do not react with thymocytes but label a splenic lymphocyte population not labelled by mAb 34.38.6. The proportion of surface immunoglobuline-positive (sIg+) lymphocytes in spleen is not altered by thymectomy. MAb 33.101.2 labels 40-48% of splenic lymphocytes, 33.45.1 stains only 14% of these same cells. This suggests some interesting heavy-chain isotypic differences in axolotl. For the first time in urodele amphibians, mAbs differentiate T-like and B-like lymphocyte populations by their membrane markers. This will allow further analysis of the axolotl immune system. [ABSTRACT FROM AUTHOR]

Spleen cells from MRL-lpr/lpr, CBA and BALB/c mice were cultured in vitro and assayed for production of anti-nuclear antibodies. Spleen cells from all species produced IgM antibodies to a nRNP (Ul-RNP)-specific antigen and to double-stranded DNA (dsDNA) after stimulation with LPS. The specificity of the anti-nRNP antibodies was shown, by immunoblotting, to be directed against the 33,000 MW polypeptide of nRNP/Sm. CBA mice produced more IgM autoantibody in vitro than MRL/lpr or BALB/c mice. In contrast, IgG anti-nRNP and anti-dsDNA antibody were not produced by any of the strains. Our data show that anti-nRNP and anti-dsDNA precursor B cells are part of the normal murine immune repertoire and are not confined to the MRL/lpr strain. This suggests that the spontaneous development of anti-nRNP and anti-dsDNA antibodies associated with systemic lupus erythematosis (SLE) is dependent on clonal stimulation and removal of suppressive influences. [ABSTRACT FROM AUTHOR]

A method for the isolation of lymphocytes and epithelial cells from the murine gastric mucosa has been developed. Gastric lymphocytes were stimulated by T-cell mitogens in vitro. When mice were sensitized systemically with human gammaglobulin (HGG) and given the antigen orally 4 days before cell isolation, both the number of mucosal lymphocytes and their capacity to incorporate [3H]thymidine ([3H]TdR) was enhanced. Gastric epithelial cells added to cultures of syngeneic spleen cells enhanced both phytohaemagglutinin (PHA) responsiveness and mixed lymphocyte reactions (MLR) in low numbers, but significantly suppressed these responses at high concentrations. These findings suggest that gastric lymphocytes, like those of the gut, are involved in the immune response against antigens taken in by mouth, and that there may be in vivo interactions between gastric mucosa lymphocytes and epithelial cells. [ABSTRACT FROM AUTHOR]

We have established a new method for pancreatic allografts in mice by combining pancreatic transplantation with allogeneic bone marrow transplantation. In this approach, we first transplanted bone marrow to induce tolerance to both donor-type and host-type major histocompatibility complex (MHC) determinants. Pancreatic tissue from the same mouse strain as bone marrow donor was then grafted under the renal capsule Acceptance of the grafts was confirmed by histopathological and immunohistochemical techniques. BALB/c mice reconstituted with C57BL/6J bone marrow cells accepted pancreatic tissue from both bone marrow donor (C57BL/6J)-type and host (SALB/c)-type mice. An immunohistochemical study revealed the presence of functional islets under the renal capsules. Assays for both mixed lymphocyte reaction (MLR) and induction of cytotoxic T lymphocytes indicated that the newly developed T cells are tolerant of both donor (stem cell)-type and host-type MHC determinants. By contrast, the T cells of these chimeras showed a significant responsiveness to third party MHC determinants. These findings suggest that pancreatic allografts combined with bone marrow transplantation may become a viable strategy for the treatment of patients with diabetes or patients who have undergone pancreatectomy. [ABSTRACT FROM AUTHOR]

Antigen-specific T-helper factor (ThE) bears I-A determinants and is I-A restricted in its action. This I-A restriction may be explained by ThF binding, and hence approximating antigen to its own I-A determinants, thereby facilitating recognition by the T cell (I-A presentation theory), or by a recognition site for I-A on the ThF which approximates the antigen to I-A+ antigen-presenting cells (I-A recognition theory). When ThF is produced in F1 mice there may be a dissociation between the I-A phenotype of the ThF and the I-A restriction of any recognition site for I-A. In practice, ThF is made by spleen cells from (CBA × B10)F1 [(H-2k × H-2d)F1] mice pretreated with cyclophosphamide (100 mg/kg) and immunized with picrylated parental spleen cells intravenously (3 × 107). This procedure produces haplotype-restricted contact sensitivity (corresponding to the parental cells) but the unfractionated F1 ThF does not show haplotype-specific restriction in its action. In fact, the F1 mice produces two species of ThE, each bearing determinants of the I-A molecule of one parental haplotype (k or d). When the two species were separated with monoclonal anti-I-Ak and anti-I-Ad antibodies, the genetic restriction in their action corresponded to the phenotype of the I-A determinants that they carried. In a further experiment, F1 ThE was split into its constituent antigen-binding (Ag+ )and antigen non-binding (Ag-)chains by reduction, and the two species of Ag- chains separated with monoclonal anti-I-A antibodies. After complementation with the Ag+ chain, the two species of Ag- chains showed genetic restriction in their action that corresponded to the phenotype of the I-A determinants that they carried. These findings support the I-A presentation hypothesis that antigen-specific ThE acts by approximating antigen to its own I-A determinants, and hence facilitates recognition by I-A-restricted I cells. [ABSTRACT FROM AUTHOR]

Properties of macrophages isolated from Peyer's patches were compared with properties of peritoneal macrophages. We found a very low expression of all types of Fc receptors as well as a low expression of Ia antigens on Peyer's patch macrophages. No substantial changes in the levels of FcR and [a antigen expression were found during the process of ageing. The investigation of phagocytic activity showed the activated state of Peyer's patch macrophages. Comparing the surface markers of lymphocytes obtained from Peyer's patches of mice of different ages, we found no differences in the numbers of sIg+, Thy-+ or L3T4+ lymphocytes. The numbers of FcR+ and Lyt 2.2+ lymphocytes decreased markedly with age. [ABSTRACT FROM AUTHOR]

The generation of secondary suppressor T (Ts) cells has been studied during latent Japanese encephalitis virus (JEV) infection of mice. The mice infected with JEV 27 weeks earlier, on challenge with the homologous virus, showed accelerated generation of secondary Ts cells; these appeared on Day 6, with peak activity on Day 8, and lasted for 27 days. The secondary Ts cells were Thy 1.2+, Ly l-2+, antigen-specific, and acted in a dose-dependent manner. The secondary Ts cells could also be generated by reactivation of the JEV in latently infected mice. The findings thus show the presence of memory suppressor T cells in mice latently infected with JEV that can be stimulated to produce secondary Ts cells by exogenous or endogenous virus challenge. This phenomenon could help to persistence of the virus. [ABSTRACT FROM AUTHOR]

When BALB/c bone marrow cells were transferred to lethally X-irradiated C3H/He mice either intrasplenically (i.s.) or intravenously (i.v.), suppressor cells were detected by means of MLR coculture assays in the spleen of i.s. and i.v. chimaeras. Some but not all of the suppressor cells expressed a Thy 1.2 antigen, indicating that suppressor cells either sensitive or insensitive to anti-Thy 1.2 antibody plus complement treatment were generated in the spleen of i.s. and i.v. chimaeras. According to the examination of Lyt alloantigen expression on suppressor T cells, Lyt l+2 , Lyt 1+2+ , and Lyt 1 + 2+ suppressor T cells appeared to be present. The culture supernatants from several T-cell clones showed the suppressor activity against alloreactive M LR. Cell surface markers of these clones were composed of Lyt 1+ 2-, Lyt 1+ 2 - and Lyt 1- 2+. In addition, since Carrageenan treatment abrogated the suppressor activity of plastic dish adherent cells, we conclude that some of them were composed mainly of macrophages. [ABSTRACT FROM AUTHOR]

PPD-reactive T cell clones have been used to analyse the nature of T lymphocytes that are involved in the 'heterogenization' of turnout cells. This is a phenomenon where coupling turnout cells to a strong antigen (in this case PPD) causes an enhanced immune response to tumour-specific antigens to be elicited providing that the host shows T cell immunity to the strong antigen (in this case is BCG positive). Clones of T cells with the Lyt1+ 2- phenotype which were unable to mediate delayed-type hypersensitivity but which provided efficient help to hapten-primed B cells were found to potentiate anti-turnout immunity in BCG-negative syngeneic mice when immunized with Con-A-PPD coupled, X-irradiated MC6A tumour cells. There therefore appears to be a mechanism whereby a helper T cell response to one antigen can provide help for the generation of a T cell response to a linked antigen which is analogous to the well-known phenomenon of help to hapten primed B cells. Furthermore the clones of T cells that help B cells the best are those that give maximal augmentation of T cell immunity. [ABSTRACT FROM AUTHOR]

A system is described which involves an in-vivo and an in-vitro step for the generation of strong primary cytotoxic T lymphocyte (CTL) responses to multiple minor alloantigens. The protocol consists of immunizing mice in the footpad with irradiated, minor alloantigen-different spleen cells. Four days later, cells from the lymph nodes draining the site of injection are cultured for 3 days in the absence of antigen to allow the development of cytotoxic activity. The analysis of the effector phase of the response indicates that the killer cells are H-2 restricted cytotoxic cells specific for minor alloantigens. The in-vitro phase of these cytotoxic responses is I cell-dependent and the responder cells proliferate strongly during the culture period. Both cytotoxic and proliferative responses are abolished by passing responder cells over Sephadex G-10 prior to culture. The results suggest that the maturation process of CTL-precursor (CTL-P) cells into effector CTL in vitro depends upon proliferating T cells and accessory cells. [ABSTRACT FROM AUTHOR]

Normal lymphocytes labelled with 51Crk were injected into mice at various stages of lethal and non-lethal malaria infections. Marked alterations were seen in the uptake into spleen and liver, which correlated with the outcome of the infection. Non-lethal infections and lethal infections in mice protected by vaccination caused increased uptakes, especially in the liver. In lethal infections, particularly Plasmodium berghei, uptakes were below normal values at certain times: this was apparently due to destruction of lymphocytes, probably caused by autoantibody. [ABSTRACT FROM AUTHOR]

Female mice of the NMRI strain were injected with 5 μg diethylstilboestrol (DES) or oestradiol-17β for the first 5 days after birth. Controls were given olive oil only. At the age of 4–6 months, the spleen lymphocyte population from the DES females had about half the percentage of cells undergoing capping after exposure to concanavalin A (Con A) as controls. The results from the oestradiol-injected females varied. After treatment of lymphocytes from DES females with colchicine, the percentage cells capping was as in control females. Binding studies did not reveal any difference in Con A receptor affinity or receptor number between DES females and controls. [ABSTRACT FROM AUTHOR]

The article presents a study which analyzed mouse lymphocytes for their cytolytic activity in complete or Ca2+ deprived medium. The data indicate that direct comparison of cytolysis in complete and deprived medium showed no difference between effectors with respect to adherence to nylon wool, sensitivity to lysis, or rate of cytolysis.

The ontogeny of the capacity of the B-lymphocyte population to produce a response which is heterogeneous with respect to antibody affinity was studied in a cell transfer system. Lethally irradiated mice were reconstituted with B cells from donors of various ages, together with adult thymus cells when the response to T-dependent antigens was studied. The animals were immunized with one of a variety of antigens one day after cell transfer and the distribution of their splenic plaque-forming cells (PFC) with respect to affinity was assayed, by hapten inhibition of plaque formation, 2 to 3 weeks after immunization. Mice reconstituted with B cells from neonatal donors produced a response of low affinity and restricted heterogeneity. With four different thymic-dependent antigens (DNP-BGG, F-BGG, DNP-KLH and Dan-KLH) the splenic B-cell population acquired the capacity to reconstitute irradiated mice to produce a normal adult-like, highly heterogeneous, high affinity PFC response between 7 and 10 days after birth. The capacity to produce a heterogeneous response to the thymic-dependent protein antigen BGG matured just slightly later, between 10 and 14 days of age. The bone marrow matures with regard to the capacity to reconstitute irradiated mice to give a heterogeneous response several days after the spleen, possibly as a consequence of the redistribution of peripheral B cells to the bone marrow. In contrast, maturation of the capacity of the splenic B-cell population to reconstitute irradiated recipients to give a heterogeneous, adult-like PFC response to three 'thymic-independent' antigens (TNP-PA, DNP-Ficoll and TNP-BA) takes place considerably later (between 3 and 4 weeks of age). These results suggest that the population of B-cell precursors which responds to thymic-dependent antigens may represent a different subpopulation of B cells from the population that responds to thymic independent antigens. Furthermore, the results suggest that these B-cell subsets mature at different times, presumably under independent controls. [ABSTRACT FROM AUTHOR]

Mouse spleen lymphocytes were stained with rabbit antisera specific for either μ chain or δ chain, followed by fluorescein-conjugated goat anti-rabbit immunoglobulin. The cells were analysed and fractionated using a fluorescence-activated cell sorter. Fifty-five per cent of the lymphocytes stained with a polyspecific anti-Ig reagent or with a combination of anti-μ and anti-μ reagents, while about 40% of the lymphocytes were stained when either the anti-δ reagent or the anti-δ reagent was used alone. Three per cent of the lymphocytes stained with the anti-δ reagent, but not with the anti-δ reagent, and eight per cent stained only with the anti-δ reagent. Unfractionated spleen cells and populations depleted of p-or δ-bearing cells were cultured in the presence of lipopolysaccharide. All three populations responded by incorporating [³H]-thymidine and secreting IgM and IgG. Spleen cells were fractionated by a rosetting technique into complement receptorpositive and negative populations. Both populations were able to respond to lipopolysaccharide and to synthesize Ig of both the IgM and IgG classes. Unfractionated cells and complement receptor-negative populations were stained for surface μ or δ chain and analysed on the fluorescence-activated cell sorter. The distribution of staining intensity suggested that the complement receptor-bearing population was enriched in cells which stain weakly for μ and cells which stain with a low to intermediate intensity for δ chain. It is concluded that the precursors of IgM- and IgG-secreting cells are not limited to any one of the three populations of cells defined on the basis of surface immunoglobulin or to either of the populations defined on the basis of the complement receptor. [ABSTRACT FROM AUTHOR]

Following the implantation of syngeneic chromosomally marked thymuses under the kidney capsule of normal adult mice, donor T cells were found in the blood and other lymphoid organs. The mice were found to have increased numbers of Thy.1-pusitive cells in spleen and lymph nodes, increased peripheral blood lymphocyte levels and also augmented immune responses to sheep erythrocytes. The contribution made by an individual graft to the donor T cell pool was independent of the number of thymuses grafted as was the growth of the grafts themselves. The results reaffirm that there is no homeostatic feedback control of thymus growth in adult mice. [ABSTRACT FROM AUTHOR]

The distribution of radioactivity after the intravenous injection of 51Cr-labelled human lymphocytes has been examined in normal mice, irradiated mice, mice treated with anti-platelet antiserum and in mice treated with colloidal carbon. Pre-treatment with carbon and anti-platelet antiserum appears to protect the human lymphocytes from uptake by the host's reticuloendothelial system (RES). Comparison of tissue radioactivity in carbon-treated mice after the injection of viable human lymphocytes with that found after the injection of dead cells and soluble or insoluble cell debris showed that radioactivity recovered in the spleen and lymph nodes is primarily due to the migration of viable lymphocytes into these tissues. Thus the measurement of radioactivity in lymph nodes of carbon-treated mice after the injection of 51Cr-tabelled human lymphocytes can be used as a model of these lymphocytes' ability to migrate into the lymph nodes during recirculation and to study factors influencing this migration. [ABSTRACT FROM AUTHOR]

Splenic immune responses having varying dependence on accessory cell co-operation have been studied after infection of mice with Friend virus. Infection has no effect on cell proliferation or antibody production in cultures stimulated with E. coil lipopolysaccharide. The response in vivo to type III pneumococcal polysaccharide is depressed only moderately. The response to sheep red blood cells is depressed severely both in vivo and in vitro. Depression in vitro is greatly reduced by co-stimulation with E. coil lipopolysaccharide. Depletion of potential suppressor lymphocyte populations by irradiation or adult thymectomy does not ameliorate depression of responses to sheep red blood cells or pneumococcal polysaccharide. Responses after adult thymectomy plus irradiation are not affected by the virus. Although it is known that macrophage and helper T-lymphocyte co-operation are not themselves impaired by infection, these results suggest that there is a direct relationship between severity of immune expression and dependence on co-operation. Implications for the action of the virus are discussed. [ABSTRACT FROM AUTHOR]

The present studies reinvestigate the role of the T cell in the development of resistance to Listeria monocytogenes. Doubly thymus-deprived adult thymectomized irradiated bone marrow-reconstituted mice (D-AT × BM) were prepared using anti-theta serum-treated bone marrow from AT × BM donors for reconstitution. The growth of the bacteria in spleens and livers of D-AT × BM was inhibited and such animals survived infection with doses which were lethal to normal mice. Since the D-AT × BM animals were T cell-depleted. as evidenced by (a) absence of theta-positive cells in their spleens; (b) inability to mount a primary humoral response to a T-dependent antigen and (c) failure to reject H-2 incompatible skin allografts, their antibacterial resistance was not due to the presence of a residual T-cell population. Further evidence of T-cell depletion in these animals was furnished by the findings that, despite their resistance to L. monocytogenes, they failed to exhibit a delayed hypersensitivity reaction to Listeria antigens, their splenocytes were unable to transfer resistance to naive hosts and they did not develop an anamnestic response upon secondary challenge. We concluded from these findings that primary antibacterial resistance to L. monocytogenes need not necessarily depend on the development of specific cell-mediated immunity although under normal circumstances these two processes develop in chronological association. The increased resistance of D-AT × B M animals is interpreted as being due to the enhancement of bactericidal activity of mononuclear phagocytes, possibly caused by the removal of a regulatory T-cell population. This population seems to be radiosensitive and spleen-seeking and requires an intact spleen to mediate its effect. [ABSTRACT FROM AUTHOR]

Male and female spleen cells were compared before and after culture for their cytotoxicity to autologous-embryo fibroblasts. Cultures of male cells developed significantly greater reactivity than cultures of female cells. Moreover, while the cytotoxicity derived from cultures of male cells was totally abolished by treatment of effector cells with a mouse anti-T cells antiserum, such an antiserum had less affect on the effector cells of female mouse cultures. [ABSTRACT FROM AUTHOR]

Cultured female spleen cells develop less cytotoxicity to embryo-associated antigens than do cultured male spleen cells. This difference is less pronounced if the cells are treated before culture with a specific hetero-anti-B cell antiserum. Female non-T cells (especially from primiparous animals) can decrease the spontaneously developing T-cell cytotoxicity in male splenic T lymphocytes upon culture. By artificially manipulating the T cell: non-T cell ratio in the spleen population prior to culture, it seems one can alter the type of cytotoxic mechanism (to embryo-associated antigens) which develops in the cultures. [ABSTRACT FROM AUTHOR]

The primary and secondary responses to ∅X174 have been studied in T cell-deprived (T-) and control CBA mire including sham-operated (T+) and normal mice. The effect of pertussis on the immune response of these mice has been measured. It is concluded that: (1) the γG and memory responses to ∅X are produced in T - mire even though greatly reduced in comparison with T+ and normal mice; (2) pertussis appears to enhance the γG response in T- mice while suppressing it in T + and normal mice. [ABSTRACT FROM AUTHOR]

The mouse Nrampl (Bcg) gene on chromosome 1 exerts pleiotropk effects on macrophage function. The gene is known to affect presentation of mycobacteria, and other antigens in vitro, so that macrophages carrying the resistant Bcg allele better support the proliferation of antigen-specific T cells compared with macrophages of the sensitive phenotype. To determine whether the Bcg allele could affect in vivo the antibody response to antigens not related to mycobacterial infections, we tested the primary and secondary responses to sheep red blood cells (SRBC) and glycosylated bovine insulin (G-insulin) in two pairs of Bcg congenic strains: BALB/c (Bcgs) versus BALB/c.CD2 (Bcgr), and B10.A (Bcgs) versus B10Ar (Bcgr), and in C57BL/10ScSn (B10; Bcgs) and A/J (Bcgr) mict. Furthermore, the antigen-specific proliferative responses of T cells primed in vivo by protein antigens were also tested in Bcg congenic mice. We found no significant difference in vim antibody response either to SRBC or G-insulin between the Bcgr and Bcgs strains. The magnitude of in vitro antigen-specific proliferation of lymph node cells sensitized in vivo by hen egg lysozyme (HEL) or chicken ovalbumin (OVA) was also similar in Bcgs and Bcgr congenic mice. However, we have documented a higher antigen-presenting capacity of Bcgr macrophages in vitro antigen-specific proliferation to OVA. Since the macrophages are the only cells in which the Nrampl gene is expressed, we suggest that the activity of other types of antigen-presenting cells masks the effect of the Bcgr allele on antigen-presentation in vivo. [ABSTRACT FROM AUTHOR]

A chronic viral infection can occur when the host fails to mount an effective immune response to clear the virus. Mouse hepatitis virus type 3 (MHV3) appears to be an excellent model for the study of the relationship between viral-induced immunodeficiency and chronic disease development. (C57BL/6 × A/J)F1 mice surviving acute hepatitis develop a chronic disease characterized by T- and B-cell immunodeficiencies, viral persistence in various organs including the brain, spleen and thymus, and death within 3 months postinfection (p.i.). We have reported that T- or B-cell deficiencies, observed in MHV3 chronically infected (C57BL/6 × A/J)F1 mice, can be partially or totally thwarted by adoptive transfer of CD4+, CD8+ and/or B cells, at 15 days p.i. in mice surviving the acute phase of the disease. Adoptive transfer of syngeneic CD4+ and/or CD8+ allowed a partial restoration of the T-cell deficiencies, as characterized by thymic atrophy, decrease in splenic T cells, and in all thymocyte subpopulations. B-cell immunodeficiency, as defined by a decrease in splenic B cells, as well as in the bone marrow pre-B- and B-cell compartments, and the occurrence of abnormally larger forms or bone marrow pre-B and B cells, were partially thwarted by B-cell treatment only. Splenic B cells and the bone marrow B-cell compartment, respectively, returned partially or totally to normal values, whereas the pre-B-cell compartment remained depleted in infected mice treated with B cells. Levels of all immunoglobulin classes returned to normal values in MHV3 chronically infected mice when treated with CD4+ in combination with CD8+ cells. All T- and/or B-cell treatments, however, were sufficient to thwart the process of the chronic disease, and favoured the survival of mice for up to 6 months p.i. [ABSTRACT FROM AUTHOR]

After their primary differentiation and selection in the bone marrow, the cells of B lineage are distributed to the peripheral lymphoid system. Here we report that, with the use of a novel rat monoclonal antibody (IBL-2), a tissue-related phenotypic difference could be observed in the peripheral B-cell compartment in mouse. The antigen recognized by this antibody is a 25000/ 29000 MW heterodimeric cell surface molecule which is resistant to phosphatidylinositol-phospholipase C treatment, but is sensitive to proteases. The antigen was found to be expressed by the majority of B cells from the spleen, whereas the B cells from other peripheral sources (lymph nodes and Peyer's patches) proved to be negative. The staining pattern of splenic B cells was heterogeneous, containing a substantial dim population (IBL-2lo), and a smaller, intensely stained fraction (IBL-2ht) within the positive subset. Unlike the B cells, the T cells were negative in every peripheral lymphoid tissue analysed. In addition, the ratios between the various IBL-2-reactive B cells (positive to negative and, within the positive population, the IBL-2lo to lBL-2ht, respectively) in the spleen were quite similar to that of B cells in the bone marrow. Furthermore, the levels of L-selectin expressed by the various IBL-2-reactive subpopulations were found to be heterogeneous both in the bone marrow and in the spleen. The bone marrow cells could be resolved into double negative, L-selectin±/IBL-2lo, L-selectin--IBL-2lo, and L-selectin-/IBL-2ht populations, respectively, in the spleen, an additional fraction with L-selectin+/IBL-2- phenotype could be detected. In both tissues, the overwhelming majority of IBL-2ht cells were found at the MEL-14- compartment. We conclude that either these findings may reflect a heterogeneous development state within the peripheral B-cell pool, with a substantial fraction of splenic B cells being less differentiated than those in other peripheral lymphoid tissues, or alternatively, the differential reactivity of murine B cells with the IBL-2 monoclonal antibody is due to their tissue location. [ABSTRACT FROM AUTHOR]

There has been disagreement about the ability of exogenous interleukin-2 (IL-2) to restore responsiveness to lymphocytes From either Trypanosoma cruzi-infected animals or normal individuals co-cultured with this parasite. The discrepancy has been attributed to the use of different strains of mice or T. cruzi isolates, or to the use of lymphoid cells from different organs. As T. cruzi inhibits the expression of IL-2 receptors by activated lymphocytes in vitro, we were able to test whether restoration of responsiveness by exogenous IL-2 might depend on the level of suppression present in the system. Human or mouse lymphocytes stimulated with phytohaemagglutinin (PHA) exhibited gradual decreases in IL-2 receptor expression, [³H]thymidine incorporation and IL-2 secretion as the concentration of T. cruzi in the culture increased. Exogenous IL-2 afforded a degree of restoration of both IL-2 receptor expression and [¹H]thymidine uptake which was substantial at the lower, but very small—if any—at the higher, parasite concentrations tested. Trypanosoma cruzi could not have competed with the lymphocytes for IL-2 because it did not brad significant amounts of this cytokine. These results suggested that the controversy about the corrective effects of IL-2 may be more apparent than real, reflecting variations in the extent of immunosuppression present in different model systems of T. cruzi-associated immunosuppression. [ABSTRACT FROM AUTHOR]

We have studied proliferative responses to mycobacterial antigen preparation (PPD) and to non- specific stimuli of interstitial cells from the lungs of Mycobacterium tuberculosis-infected CRA mice. PPD-reactive lymphocytes appeared in the lung wall tissue in the course of chronic infection, but their proliferative capacity was totally inhibited by the lung macrophages. The latter were also able to suppress the proliferation of immune lymph node T cells. The mechanism of suppression clearly had two components, one being infection-specific and the other non-specific. Non-specific suppression was mediated mainly by prostaglandin E(PGE), whereas the specific mechanism showed only a weak influence of PGE and depended on the presence of I-J+ Lyt-2- nylon-wool-adherent cells in the responder population. Interstitial lung T or B lymphocytes were not involved in specific suppression. [ABSTRACT FROM AUTHOR]

Biologically active interleukin-1(IL-1) has been detected in supernatants of draining lymph node cells isolated from contact-sensitized mice. Induction of IL-1 was dependent upon the concentration of sensitizer applied and occurred within 2 hr of exposure. The IL-1 activity could not be attributed to other interleukins and was neutralized by a specific antiserum. Reduced concentrations of IL-1 were produced by cells isolated from the draining nodes of mice that had been pre-exposed to the sensitizer. Since IL-1 has the potential to influence several aspects of lymphocyte activation, the production of significant concentrations of biologically active IL-1 by draining lymph node cells indicates that it is likely to play an important role in the afferent phase of contact sensitization. [ABSTRACT FROM AUTHOR]

Lethally-irradiated mice were injected with rat bone marrow cells and examined subsequently for the presence of rat macrophages, using an indirect fluorescent antibody test in conjunction with a fluorochrome-labelled phagocytic cell marker. Donor bone marrow cells were fractionated by (1) adherence, (2) magnetic removal of phagocytic cells containing ingested carbonyl iron and (3) treatment with lymphocyte-absorbed anti-rat macrophage serum either in vitro or in vivo. Extensive rat cell proliferation occurred in the resulting xenogeneic chimaeras by or after Day 4 and increased during the next week. The precursor of both the free and fixed macrophages was contained in the non-adherent, non-phagocytic population of bone marrow cells. The anti-macrophage serum was not selective and abolished the capability of bone marrow cells to proliferate. [ABSTRACT FROM AUTHOR]

Proteolytic events might play a role during lymphocyte activation. Mouse spleen cells were therefore stimulated in serum-free cultures by PHA, ConA, LPS and dextran sulphate and the effect of various added protease inhibitors on [³H]-thymidine incorporation investigated. Both soybean inhibitor and Trasylol inhibited the response of the cells to all mitogens. The other inhibitors (antipain, leupeptin, ovomucoid, alpha-1 trypsin, alpha-2 macroglobulin) had little or no effect. The marked inhibitory effect of tosyl-lysine chloromethylketone could be neutralized by reduced glutathione, indicating an effect on intracellular glutathione rather than on proteases. [ABSTRACT FROM AUTHOR]