Polyclonal Antibody Production in Murine Spleen Cells Induced by Staphylococcus

Polyclonal plaque-forming cell (PFC) responses in murine spleen cells induced by Staphylococcus aureus and S. epidermidis were studied. Injection of Balb/c mice with S. aureus strain 248βH resulted in the generation of anti-trinitrophenyl (TNP) and anti-sheep red blood cell PFC in their spleens. Cultures of Balb/c spleen cells in the presence of S. aureus 248βH, Cowan I, or a protein A-deficient mutant yielded many anti-TNP PFC. The larger the number of organisms that were added to the cultures, the better was the PFC response. Both living and killed organisms, were capable of inducing the response, but an excess of living 248βH organisms in the cultures abrogated the response. All of the organisms (12 strains of S. aureus and 11 strains of S. epidermidis) freshly isolated from patients had the ability to induce the polyclonal PFC response in cell cultures. These organisms stimulated cultured C3H/HeJ mouse spleen cells, which were unresponsive to bacterial lipopolysaccharide (LPS). Cultured cells from the spleens of athymic nu/nu mice also responded to these organisms, and the number of PFC in nu/nu cell cultures was always greater than that in nu/+ cells prepared from a haired litter mate. Moreover, the responses of nu/nu spleen cell cultures to which nylon wool column-filtered splenic nu/+ T cells were added were lower than expected. These findings suggest that the polyclonal PFC response to staphylococci is thymus independent, but that the magnitude of the response is regulated by mature T cells. Cultures of macrophage-depleted spleen cells responded to the organisms to an extent similar to that of the control. The 248βH organisms were less capable of stimulating spleen cells of 2-week-old mice (i.e., early maturing B cells) than LPS. However, spleen cells from adult (7-week-old) and aged (9-month-old) mice responded well to both the organisms and LPS. Previous sensitization with the organisms in vivo did not affect any polyclonal responses of spleen cells in vitro to either the organisms or LPS. The role of staphylococcal protein A in the polyclonal PFC response to staphylococci is discussed.     

Mitogenic Activity of the Cell Walls of Mycobacteria,Nocardia, Corynebacteria and Anaerobic Coryneforms

The mitogenic activity of the cell walls prepared from Mycobacterium bovis BCG, Nocardia rubra, Corynebacterium diphtheriae PW8, and four species of Propionibacterium, Corynebacterium parvum ATCC 11829, Propionibacterium acnes C7, Propionibacterium granulosum ATCC 25564 and Propionibacterium avidum ATCC 25577, were investigated. These cell walls were active as mitogens on normal spleen cells, anti-θ sera-treated spleen cells, macrophage-depleted spleen cells of C57BL/6J mice and cortisone-treated thymocytes of C57BL/6J mice. It was also shown that these cell walls were mitogenic on spleen cells and macrophage-depleted spleen cells of congenitally athymic (nude) mice. The above results suggest that the cell walls investigated in this study act as mitogens on both thymus-derived lymphocytes (T-cells) and bone marrow-derived lymphocytes (B-cells).     

B Cell Tolerance

The mechanisms of B cell tolerance were studied in an attempt to learn whether B cells rendered tolerant are present in the immune system in a potentially responsive form. The author tested the in vitro anti-trinitrophenyl (TNP) antibody-forming cell (anti-TNP AFC) response to TNP-immunogens and polyclonal B cell activators (PBA) of spleen cells taken from mice injected with a tolerogen, TNP-carboxymethylcellulose (TNP-CMC). Spleen cells from mice injected 5 days previously with 10 μg of TNP-CMC did not respond to TNP-sheep red blood cells (TNP-SRBC), T-dependent (TD) antigen or TNP-Ficoll, T-independent (TI) antigen. However, the same spleen cells responded to PBA, lipopolysaccharide (LPS) of Salmonella enteritidis and purified protein derivative (PPD) of BCG. The results indicate that B cells specific for TNP are present in a potentially responsive form. Spleen cells from mice injected with 500 μg of TNP-CMC did not respond to either TNP-immunogens or PBA. The state of unresponsiveness to PBA lasted for 12 days after the tolerogen injection. Responsiveness to PBA reappeared within the short period of 2 days, whereas unresponsiveness to TNP-immunogens lasted much longer. Unresponsiveness to PBA was relieved considerably by treating tolerant spleen cells with the proteolytic enzyme trypsin before in vitro stimulation. These results indicate that B cells rendered refractory are present in the immune system in a potentially responsive form.     

In Vitro Proliferative Response and Polyclonal Antibody Production in Spleen Cells of Immunologically Defective CBA/N and C3H/HeJ Mice by Water-Soluble Adjuvant (Bu-WSA) Extracted from Bacterionema matruchotii

Mitogenicity and the polyclonal plaque forming cell(PFC)-inducing property of a water soluble-adjuvant extracted from Bacterionema matruchotii by butanol (Bu-WSA) were examined in vitro in the spleen cells of hybrid (CBA/N female × BALB/c male) F1 mice and C3H strain of mice. The hybrid F1 male cells which expressed a CBA/N-defect were unable to respond to Bu-WSA, when assessed by the incorporation of [³H] thymidine into the cells and the generation of anti-trinitrophenyl (TNP)-PFC or autoantibody PFC defined by the anti-bromel-ain-treated mouse erythrocyte PFC assay. However, hybrid F1 female cells with normal traits responded to Bu-WSA. Cultured spleen cells of bacterial lipopolysaccharide (LPS)-nonresponsive C3H/HeJ mice responded to Bu-WSA as in the case of cells of LPS-responsive C3H/He mice, and the [³H]thymidine-uptakes and the numbers of PFC in these culture cells increased. Re-extraction of Bu-WSA by phenol did not affect its activities, while the activity of butanol-extracted LPS on C3H/HeJ cells decreased after re-extraction by the same procedure with phenol.     

Serological properties and immunobiological activities of lipopolysaccharides from black-pigmented and related oral Bacteroides species

Lipopolysaccharides (LPS) from five species of oral Bacteroides, B. gingivalis strains 381 and ATCC 33277, B. oralis ATCC 33269, B. loescheii ATCC 15930, B. intermedius ATCC 25611 and B. corporis ATCC 33547, were extracted from whole cells by the phenol/water procedure, and subsequently purified by treatment with nuclease and ultracentrifugation. The LPS were composed of hexoses, glucosamine, fatty acids and phosphorus. Heptose and 2-keto-3-deoxyoctonate were not detected. The LPS preparations from B. gingivalis strains 381 and ATCC 33277 presented very similar SDS-polyacrylamide gel electrophoresis patterns when stained with ammoniacal silver. They produced a fused precipitin band against an antiserum to B. gingivalis 381 LPS in immunodiffusion tests. Antisera raised against the LPS from B. loescheii and B. intermedius reacted with the LPS prepared from all the oral Bacteroides strains except those of B. gingivalis. All the LPS preparations were mitogenic for spleen cells of BALB/c (nu/nu) mice, but not for thymus cells from C3H/HeN mice. The LPS induced marked mitogenic responses and polyclonal B cell activation for spleen cells of not only C3H/HeN (LPS responder) mice, but also C3H/HeJ (LPS nonresponder) mice. The mitogenic responses were not suppressed significantly upon addition of polymyxin B to the reaction mixture. These LPS also enhanced interleukin-1 production by murine peritoneal macrophages and mouse cell line J744. 1 macrophages. Hydrolysis of B. gingivalis ATCC 33277 LPS in 1 m-HCl at 100 degrees C for 1 h yielded lipid and polysaccharide. The lipid portion was largely composed of fatty acids and glucosamine, and was mitogenic for spleen cells from C3H/HeJ as well as C3H/HeN mice, while the polysaccharide portion induced no significant mitogenic responses under similar experimental conditions.     

Immunobiological properties of lipopolysaccharides isolated from Fusobacterium nucleatum and F. necrophorum

Lipopolysaccharides (LPSs) were isolated from Fusobacterium nucleatum ATCC 10953 and F. necrophorum ATCC 25286 by the hot phenol/water procedure. F. nucleatum LPS was composed of 16% (w/w) carbohydrate, 10% (w/w) hexosamine and 40% (w/w) fatty acid, while F. necrophorum LPS was composed of 26% (w/w) carbohydrate, 12% (w/w) hexosamine and 28% (w/w) fatty acid. These LPS preparations induced mitogenic responses in spleen cells of BALB/c, BALB/c (nu/nu) and C3H/HeN mice, and these responses were suppressed by the addition of polymyxin B. The preparations also induced the polyclonal responses of C3H/HeN spleen cells. In addition, enhanced glucose utilization and interleukin-1 production by murine peritoneal macrophages were demonstrated. Neither spleen cells nor macrophages from the 'LPS-nonresponsive' C3H/HeJ mouse were activated by LPSs from the Fusobacterium species.     

Abnormal polyclonal B cell activation in NZB/NZW F1 mice

Spleen cells from autoimmune (10-mont-old) NZB/NZW (B/W) mice failed to generate appreciable numbers of antibody-forming cells (AFC) in vitro to TNP-substituted sheep erythrocytes in response to the polyclonal B cell activators (PBA), LPS and PPD, despite normal DNA synthetic responses to these agents and normal AFC responses to TNP-Ficoll. The failure to respond to PBA in old B/W mice was not due to suppressor T cells since anti-brain-associated-theta-treated spleen cells still failed to generate AFC in response to PBA. The defect was age-related since cells from young B/W mice generated vigorous AFC responses to PBA. It is suggested that the failure of the spleen cells of old B/W mice to generate AFC is a result of in vitro polyclonal B cell activation in the course of autoantibody formation.     

In vitro studies of the genetically determined unresponsiveness to thymus-independent antigens in CBA/N mice.

The X-chromosome-linked B lymphocyte defect of CBA/N mice has been studied in vitro by comparing the ability of (CBA/N X DBA/2)F1 (X-/X- X X+/Y) male (X-/Y) and female (X-/X+) spleen cells to respond to the thymus-independent antigen DNP (or TNP)-AECM-Ficoll. (CBA/N X DBA/2)F1 male spleen cells failed to generate significant in vitro anti-TNP antibody responses to DNP- or TNP-AECM-Ficoll, in contrast to spleen cells from F1 female (X-/X+) mice which responded normally to these T-independent antigens. Spleen cells from male F1 mice responded almost as well as F1 female cells to the thymus-dependent antigen, TNP-sheep red blood cells (TNP-SRBC) in vitro. Adding F1 male cells to F1 female cells failed to reduce the response of the latter to DNP-AECM-Ficoll, suggesting that the inability of F1 male cells to respond was not due to active suppression. The response of F1 male spleen cells to TNP-SRBC was not impaired by adding high concentrations of TNP-AECM-Ficoll indicating that the mechanism of unresponsiveness was not tolerance induction in all TNP-specific precursors. Lymphocytes from F1 male mice were capable of forming anti-TNP antibody after stimulation with lipopolysaccharide (LPS) in high concentrations; DNP-AECM-Ficoll had no effect on this polyclonal response. B lymphocytes from mice bearing only the X-chromosome of the CBA/N strain thus display a profound defect in B cell activation. This functional defect may represent either an inability of the defective B cells to be activated by thymus-independent antigens or the absence of a sub-class of B cells which respond to thymus-independent antigens.     

Specific Humoral Immunity versus Polyclonal B Cell Activation in Trypanosoma cruzi Infection of Susceptible and Resistant Mice

Background

The etiologic agent of Chagas Disease is Trypanosoma cruzi. Acute infection results in patent parasitemia and polyclonal lymphocyte activation. Polyclonal B cell activation associated with hypergammaglobulinemia and delayed specific humoral immunity has been reported during T. cruzi infection in experimental mouse models. Based on preliminary data from our laboratory we hypothesized that variances in susceptibility to T. cruzi infections in murine strains is related to differences in the ability to mount parasite-specific humoral responses rather than polyclonal B cell activation during acute infection.

Methodology/Principal Findings

Relatively susceptible Balb/c and resistant C57Bl/6 mice were inoculated with doses of parasite that led to similar timing and magnitude of initial parasitemia. Longitudinal analysis of parasite-specific and total circulating antibody levels during acute infection demonstrated that C57Bl/6 mice developed parasite-specific antibody responses by 2 weeks post-infection with little evidence of polyclonal B cell activation. The humoral response in C57Bl/6 mice was associated with differential activation of B cells and expansion of splenic CD21^highCD23^low Marginal Zone (MZ) like B cells that coincided with parasite-specific antibody secreting cell (ASC) development in the spleen. In contrast, susceptible Balb/c mice demonstrated early activation of B cells and early expansion of MZ B cells that preceded high levels of ASC without apparent parasite-specific ASC formation. Cytokine analysis demonstrated that the specific humoral response in the resistant C57Bl/6 mice was associated with early T-cell helper type 1 (Th1) cytokine response, whereas polyclonal B cell activation in the susceptible Balb/c mice was associated with sustained Th2 responses and delayed Th1 cytokine production. The effect of Th cell bias was further demonstrated by differential total and parasite-specific antibody isotype responses in susceptible versus resistant mice. T cell activation and expansion were associated with parasite-specific humoral responses in the resistant C57Bl/6 mice.

Conclusions/Significance

The results of this study indicate that resistant C57Bl/6 mice had improved parasite-specific humoral responses that were associated with decreased polyclonal B cell activation. In general, Th2 cytokine responses are associated with improved antibody response. But in the context of parasite infection, this study shows that Th2 cytokine responses were associated with amplified polyclonal B cell activation and diminished specific humoral immunity. These results demonstrate that polyclonal B cell activation during acute experimental Chagas disease is not a generalized response and suggest that the nature of humoral immunity during T. cruzi infection contributes to host susceptibility.     

Cell cycle analysis of lymphocyte activation in normal and autoimmune strains of mice

The spontaneous spleen cell proliferation and the proliferation induced by in vivo or in vitro stimulation with such polyclonal B cell activators (PBA) as LPS, poly rI.rC, and anti-mu were studied in normal and autoimmune mice. The various murine models of autoimmunity differ in the level of naturally occurring splenic cellular hyperactivity as well as in the ability of their spleen cells to be further stimulated in vitro by polyclonal stimulators. Both the NZB strain and the MRL/Ipr strain had markedly increased numbers and percentages of spontaneously proliferating spleen cells, whereas the BXSB strain did not. Nonautoimmune strains were found to have very small numbers of activated cells in the spleen. However, such normal strains could be induced in vivo to mimic the natural splenic hyperactivity observed in older NZB and MRL/Ipr autoimmune strains by the injection of polyclonal B lymphocyte stimulators. In contrast, old hyperactive NZB mice were not further induced to undergo proliferation by in vivo administration of such stimulators. Density-separated, T depleted, spleen cells of normal and autoimmune mice were stimulated in vitro with PBA in 48-hr cultures. Cells from old MRL/Ipr and NZB mice were abnormal in both the anti-mu response and the LPS response; BXSB mice had normal anti-mu responses. These studies suggest that there is no prerequisite for spontaneous splenic hyperactivity in the development of autoimmunity. In addition, different PBA stimulate separate subsets of B cells that differ in their state of activation in the various autoimmune strains. Finally, different B cell subsets appear to be abnormal in different types of autoimmune mice.     

T cell regulation of polyclonal B cell responsiveness. II. Evidence for a deficit in T cell function in mice with an X-linked B lymphocyte defect.

In addition to the x-linked B cell maturation deficit previously reported in CBA/N mice, a functional T cell defect has now been observed. T lymphocyte regulation of the polyclonal PFC response was studied within the context of this x-linked immunodeficiency model. The ability of 1) B cells from (CBA X CBA/CaJ)F1, male mice to respond to nonspecific T cell helper signals and 2) T cells from NCF1 male mice to provide such signals was investigated under in vitro conditions by using bacterial lipopolysaccharide (LPS) as the polyclonal activator. B lymphocytes from both male and female NCF1 mice were receptive to T cell help rendered by NCF1 female T cells. Male T cells. however, were unable to augment polyclonal B cell responses of either NCF1 male or female B cells to LPS. Treatment with ATS + C reduced the polyclonal response of female but not male spleen cells to LPS. This deficit could not be overcome by the use of greater numbers of NCF1 male T cells. The observation that this deficiency in T cell regulation is not due to active suppression suggests that the results may be attributable to an intrinsic T cell defect.     

Synergistic effects of the xid gene in X chromosome congenic mice. I. Inability of C3.CBA/N mice to respond to thymus-dependent antigens in adoptive transfer assays

The xid gene, which causes a B lymphocyte immune defect in CBA/N mice, has been bred onto the C3H/HeN background. The resulting X chromosome congenic mice (C3.CBA/N) exhibit immunologic defects that are much more profound than the defect exhibited by CBA/N mice; thus, the B cells from C3.CBA/N mice not only fail to respond to thymus-independent (TI) type 2 antigens such as TNP-Ficoll, but they fail to respond in vitro to TI-type 1 antigens such as TNP-Brucella abortus (BA) and B cell mitogens such as LPS and Nocardia water-soluble mitogen. In this paper we show that the synergistic defect seen in C3.CBA/N B cells is also elicited in adoptive transfer assays to thymus-dependent (TD) antigens such as TNP-KLH and PC-KLH, antigens to which both parental strains respond. Thus, the secondary adoptive transfer response of C3.CBA/N spleen cells is generally less than 5% of the immune response produced by CBA/N or C3H/HeN spleen cells. This synergistic defect is restricted to the C3.CBA/N B cells, since C3.CBA/N T cells can provide help to CBA/N B cells that is equivalent to the help obtained with CBA/N T cells. The low responsiveness of C3.CBA/N spleen cells to TD antigens, which is elicited in adoptive transfer assays, is not seen when the intact animal is immunized with antigen in CFA; this, intact C3.CBA/N mice produce anti-PC-KLH and anti-TNP-KLH responses only slightly lower than the responses of CBA/N mice to these same antigens. In contrast, when these mice are immunized with phenol-extracted LPS, a TI-type 1 antigen, their antibody responses are severely depressed. These data suggest that under conditions in which T cell help may be limiting or in which the intact physiology of the T and B cells has been disrupted, C3.CBA/N B cells demonstrate profound immunologic impairment; however, when adequate T cell help is available and the splenic architecture is not disrupted, their immune responses appear to progress in a normal fashion.     

LPS regulation of the immune response: separate mechanisms for murine B cell activation by lipid A (direct) and polysaccharide (macrophage-dependent) derived from Bacteroides LPS

Lipopolysaccharide (LPS) derived from Bacteroides fragilis has been reported to stimulate mitogenic responses in spleen cell cultures from the classical LPS-hyporesponsive C3H/HeJ mouse strain; however, we have shown that purified splenic B cells from C3H/HeJ mice are hyporesponsive to phenol-water extracted LPS from B. fragilis ATCC 25285 (B-LPS). In the present study, B-LPS and its purified lipid A and polysaccharide components were tested for their ability to induce mitogenic and polyclonal IgM synthesis in spleen cell and purified splenic B cell cultures from classical LPS-responsive and -hyporesponsive mice. Mitogenic responses to B-LPS and E. coli K235 LPS(Ph) of whole spleen cells (2 X 10(5) cells/culture) or purified B cells (5 X 10(5) cells/culture) from classical LPS-responsive mouse strains (C3H/HeN, BALB/c, C57BL/6J, C57BL/10Sn, and DBA/2), F1 mice (derived from crosses between LPS responsive and C3H/HeJ mice), and classical LPS-hyporesponsive mice (C3H/HeJ and C57BL/10ScN) were high, intermediate, and low, respectively. When a higher number of whole spleen cells (5 X 10(5) cells/well) were cultured, B-LPS induced high mitogenic responses in C3H/HeN, intermediate responses in F1, and lower but significant responses in C3H/HeJ cultures. Similar results were obtained when polyclonal IgM synthesis was assessed in cultures containing 1 X 10(6) cells/culture. In contrast, the purified lipid A component of B-LPS failed to induce mitogenic responses in either whole spleen or purified B cell cultures. The addition of purified splenic B cells from C3H/HeJ mice to C3H/HeN or C3H/HeJ splenic adherent cells resulted in mitogenic responses to B-LPS, implying that the hyporesponsiveness to B-LPS seen in whole spleen cell cultures from C3H/HeJ mice at the lower cell concentration was due to limiting numbers of M phi. When splenic B cells and M phi from either C3H/HeN or C3H/HeJ mice were incubated with the lipid A or the polysaccharide moiety of B-LPS, lipid A induced mitogenic responses only in C3H/HeN cultures, whereas the polysaccharide moiety induced similar responses in both C3H/HeN and C3H/HeJ cultures. These results suggest that Bacteroides lipid A does not stimulate B cells from the classical LPS-hyporesponsive C3H/HeJ mouse strain, whereas the polysaccharide moiety of B-LPS is biologically active and mediates B cell stimulation via M phi.     

Augmentation of Mouse Natural Killer Cell Activity by Lactobacillus casei and Its Surface Antigens

Lactobacillus casei YIT 9018 (LC 9018) augmented the natural killer (NK) cell activity of spleen cells from inbred BALB/c mice injected intravenously with LC 9018 or intraperitoneally with polyinosinate-polycytidylate. Augmentation of this activity by LC 9018 was also observed in male C3H/He, CBA/N, and C57BL/6 mice. The spleen cells exhibited no cytolytic activity against P815, a cell line insensitive to NK cells. The cytolytic activity of the spleen cells increased 2 days after the injection of 250 μg of LC 9018/mouse, peaked on day 3, and gradually declined thereafter. The increase caused by LC 9018 was also observed in normal and Meth A-bearing mice. In vitro treatment with anti-asialo GM1 antibody plus complement completely-abrogated the LC 9018-augmented murine NK cell activity. The NK activity on the 3rd day after LC 9018 injection was reduced by in vitro treatment with anti-Thy 1.2 monoclonal antibody plus complement to half of that observed when treatment was with complement alone. This suggests that there were two populations of NK cells in the spleen cell suspension derived from LC 9018-treated mice. One population was asialo GM1-positive and Thy 1-negative, the other was asialo GM1-positive and Thy 1-positive.     

Chemical and Immunological Studies on the Cell Walls of Propionibacterium acnes Strain C7 and Corynebacterium parvum ATCC 11829

The chemical and immunological properties of the cell walls prepared from the cells of anaerobic coryneforms, Propionibacterium acnes C7 and Corynebacterium parvum ATCC 11829, were partially investigated. The cell walls prepared from P. acnes C7 and C. parvum ATCC 11829 were composed of fatty acids, polysaccharides consisting glucose, galactose and mannose and mucopeptides consisting mainly of alanine, glutamic acid, a, ε-diaminopimelic acid, glycine, muramic acid and glucosamine. As the fatty acid constituents of the cell wall of P. acnes C7, iso-pentadecanoic acid and iso-heptadecanoic acid were detected as major components. Both cell walls prepared from P. acnes C7 and C. parvum ATCC 11829 showed potent adjuvant activity on the formation of circulating antibody and development of delayed type hypersensitivity in vivo and on the primary immune response to sheep erythrocytes in vitro, however, could not augment helper function of carrier-primed T cells and on the development of cell-mediated cytotoxicity to mastocytoma P815-X2 cells in C57BL/6J mice. It is also shown that the cell walls of P. acnes C7 and C. parvum ATCC 11829 act on mouse spleen cells as mitogen.     

Preservation of polyclonal antibody production by hybridization

The fusion of unimmunized (Balb/c × SJL)_F1, mouse spleen cells in which a polyclonal response had been induced by bacterial lipopolysaccharide with a myeloma cell line resulted in hybrid cell populations. The hybrid populations obtained elaborated antibody activity to human hemoglobin A, Keyhole Limpet hemocyanin, the dinitrophenyl (DNP) hapten, and human erythrocytes, Thus, hybridization allowed preservation of the normally transitory polyclonal response induced in mouse B cells by lipopolysaccharide. Furthermore, monospecific production of anti-DNP antibody was successfully factored out of the polyspecific production of antibodies by cloning. The expansion and subsequent injection of one of these clones into a (Balb/c × SJL)_F1 mouse resulted in the formation of an antibody-producing tumor that was successfully passed to other (Balb/c × SJL)_F1 recipients. Collection of the serum from tumor-bearing mice provided useful quantities of an anti-DNP antiserum without resort to any program of immunization whatsoever.     

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.     

Tissue responses against Cladosporium trichoides and its parasitic forms in congenitally athymic nude mice and their heterozygous littermates

The tissue responses against Cladosporium trichoides and its parasitic forms were studied using nude (nu/nu) mice and their heterozygous (nu/+) littermates of BALB/c background.1.0,0.1 and 0.01% cell suspensions were prepared from a culture broth which had been inoculated with the C. trichoides and cultured with reciprocal shaking at 27 ° C for 7 days. Sixty nu/nu or 60 nu/+ mice were divided into three groups consisting of 20 each which was allotted to one of the three cell suspensions. Each mouse was inoculated intravenously with 0.1 ml of either the cell suspensions. Two mice from each of the six groups were sacrificed at adequate intervals until 30 days after inoculation and histopathologic sections stained with H & E or by PAS were prepared from their visceral organs.There were no characteristic findings in the nu/nu and nu/+ mice inoculated with the 0.01% cell suspension. When inoculated with the 1.0% cell suspension, the brain was the favorite target organ in both groups of mice and the kidney was the second. When inoculated with the 0.1% cell suspension, brain lesions were observed only in the nu/nu mice. The susceptibility of the nu/nu mice was higher than that of the nu/+ mice.The parasitic forms in the brain of the nu/nu and nu/+ mice were slender septate true hyphae with or without polymorphonuclear leucocyte infiltrate, while in the liver, spleen and lung of both groups of mice the parasitic forms were short thick hyphae, moniliform hyphae, chlamydospores or round cells (sclerotic cells). Many giant cells containing fungal elements appeared in the liver of the nu/nu mice.     

Influence of serial passage on the infectivity and immunogenicity of Nematospiroides dubius in mice

Dobson C. and Owen M. E. 1977. Influence of serial passage on the infectivity and immunogenicity of Nematospiroides dubius in mice. International Journal for Parasitology7: 463–466. The infectivity of Nematospiroides dubius was increased for Quackenbush (Q) mice by ten serial passages through this host. At the same time C(In3)H mice became more refractory to infection with successive Q generations of the parasite. Both strains of mice rejected the most highly selected parasites more readily than parasites from the earlier generations. These responses were shown to be immunological in nature by infections in hypothymic Balb/c CBA nu/nu and nu/+ mice and to be dose dependent. The selection of N. dubius for increased infectivity in Q mice enhanced its immunogenicity in this and other mouse strains possibly because of increased genetic homogenicity in the selected populations. N. dubius selected for Q mice showed a degree of immunologieal adaptation to Q but not to C₃H mice.     

In vitro spleen cell responsiveness to various analogs of MDP (N-acetylmuramyl-L-alanyl-D-isoglutamine), a synthetic immunoadjuvant, in MDP high-responder mice

N-Acetylmuramyl-l-alanyl-d-isoglutamine (MDP), a synthetic immunoadjuvant, was incubated with spleen cells of DBA/2 or Balb/c mice and optimal responses were obtained after 4 or 5 days of culture in a serum-free medium supplemented with 2-mercaptoethanol. In contrast, lymphocytes of (C57B1/6 × AKR)F₁ hybrids responded weakly under the same conditions. The results reported here show that like in the case of DBA/2 and Balb/c strains, spleen cells of Swiss mice and of inbred AKR and CBA mice could be stimulated in vitro whereas C57B1/6 and LPS-refractory C3H/He mice did not respond. Fourteen synthetic MDP analogs (eight known to be adjuvant active and six devoid of activity) were tested in DBA/2 high-responder mice. A good correlation was observed between in vitro stimulation and the presence or absence of adjuvant activity in vivo of these compounds.