Effect of fish oil diet on immune response and proteinuria in mice

In this study, we examined the immune response and proteinuria caused by dietary polyunsaturated fatty acids in normal NZW/N and autoimmune NZB/NZW mice. Mice were maintained more than one year on five dietary groups: normal (5% corn oil), calorie-restricted, high fat (20% corn oil), high fat (20% fish oil), and Purina laboratory rodent chow. Normal mice fed with the fish oil diet had a more reduced anti-sheep red blood cells (SRBC) plaque-forming cell (PFC) response and less interleukin-2 (IL-2) enhancement of PFC than did the group with the restricted diet and the young control group. The corn oil (5 and 20%) diet animals also showed reduced PFC response and IL-2 utilization. NZB/NZW mice fed with the fish oil diet showed similar reduced PFC response but had a significantly lower response to IL-2 than did those on the corn oil diets and the restricted diet. The IL-2 production by macrophages from NZW/N mice was reduced in both the fish oil and corn oil diet groups. However, mice fed with the fish oil diet had less proteinuria and good survival rates, similar to the group with the restricted diet. These results suggest that the beneficial effect of the fish oil diet in these animals may be attributed in part to the immunosuppression mechanism.     

Evidence for Genetic Basis of Seasonal Differences in Antibody Formation Between Two Mouse Strains

In order to confirm the presence of an acrophase difference based upon genotype in the seasonal expression of an immune competence end point, splenic plaque-forming cell (PFC) response to sheep red blood cells (SRBC), female B6C3F1 and CD1 mice were concurrently studied for PFC response during two studies performed in each season for 1 year. Mice were multiply housed, fed ad libitum, and standardized to light (06:00-18:00); dark (18:00-06:00). For each strain and study, subgroups were either naive (n = 10), received a vehicle (n = 10) or Cytoxan (n = 5). Challenge with SRBC occurred in early afternoon 4 days before harvesting of spleens and PFC assay. All other procedures were performed early in the daily light span. Analysis of variance and single cosinor analysis revealed a significant seasonal time effect for PFC in naive mice of both strains. Antibody formation was greatest in spring for CD1 mice and in summer for the B6C3F1 mice. These acrophases were consistent with earlier results for both strains and show the phenomena to be reproducible and genetically based.     

Evidence for Genetic Basis of Seasonal Differences in Antibody Formation Between Two Mouse Strains

In order to confirm the presence of an acrophase difference based upon genotype in the seasonal expression of an immune competence end point, splenic plaque-forming cell (PFC) response to sheep red blood cells (SRBC), female B6C3F1 and CD1 mice were concurrently studied for PFC response during two studies performed in each season for 1 year. Mice were multiply housed, fed ad libitum, and standardized to light (06:00–18:00); dark (18:00–06:00). For each strain and study, subgroups were either naive (n = 10), received a vehicle (n = 10) or Cytoxan (n = 5). Challenge with SRBC occurred in early afternoon 4 days before harvesting of spleens and PFC assay. All other procedures were performed early in the daily light span. Analysis of variance and single cosinor analysis revealed a significant seasonal time effect for PFC in naive mice of both strains. Antibody formation was greatest in spring for CD1 mice and in summer for the B6C3F1 mice. These acrophases were consistent with earlier results for both strains and show the phenomena to be reproducible and genetically based.     

Suppressors of the graft vs graft reaction in tolerance to alloantigens

Immune response and suppressor cell activity of CBA (H-2k) mice made tolerant to allogeneic C57B1/6 (H-2b) heart graft were studied in graft-versus-graft reaction (GvGR). Intact CBA spleen cells inhibited response of (CBA X C57B1/6)F1 cells to antigenic stimulus (sheep red blood cells--SRBC), when injected together into lethally irradiated (CBA X C57B1/6)F1 mice. Spleen cells of tolerant mice were unable to decrease immune response of (CBA X C57B1/6F1 lymphocytes to SRBC and suppressed specifically the inhibition induced by intact CBA spleen cells. Spleen cells from tolerant mice were also capable of suppressing GvGR induced by CBA lymphocytes immune to C57B1/6 cells. Pretreatment of tolerant spleen cells with rabbit antithymocyte globulin and complement before adoptive transfer diminished markedly the suppression. The results obtained in the study suggest that suppression of transplantation immunity in this model is mostly due to T suppressor cells.     

Suppressive action of Candida albicans on the immune response in mice.

This study was carried out to determine whether Candida albicans infection has a suppressive effect on the immune response in mice and, if so, whether the suppressive effect influences the response towards T-dependent or T-independent antigens. ICR mice were injected with SRBC with or without C. albicans, or with bacterial LPS with or without C. albicans. The immune response of the mice towards SRBC or towards the LPS was compared by the assay for PFC, hemagglutination and hemolysis tests. The results showed a decrease in the number of PFC in spleens of mice inoculated with SRBC and C. albicans as compared to mice inoculated with SRBC alone, but no decrease in animals injected with LPS and C. albicans as compared to those immunized with LPS alone. No significant differences in the titers of hemagglutinins and hemolysins in sera of mice inoculated with SRBC or with SRBC and C. albicans were observed. C. albicans infection had no effect at all on the hemagglutinins and hemolysins titers in sera of mice inoculated with LPS. These data indicate that C. albicans affects the early phase of the immune response primarily towards T dependent antigens.     

Differential immunosuppressive effects of ascites fluid from mastocytoma-bearing mice on primary vs secondary immunocyte responses.

The effects of immunosuppressive ascites fluids from mastocytoma-bearing mice on the primary vs secondary immune response to sheep red blood cells (SRBC) was examined. Injection of mice with ascites fluid from tumor-bearing mice markedly depressed the primary immune response of normal syngeneic mice challenged with SRBC. However, there was a preferential depression of the 19S IgM antibody response as compared with the 7S IgG response. Injection of ascites fluid shortly before secondary immunization of mice with SRBC also resulted in depressed IgM PFC responses but only a slight to moderate depression of IgG PFC. Treatment of mice with the ascites fluid before primary immunization had little if any effect on the secondary IgG PFC response, although the IgM response was moderately depressed. These results indicate that the immunosuppressive factor(s) present in the ascites fluid of mastocytoma-bearing mice has a differential effect on distinct classes of immunocytes. Those immunocytes or their precursors involved in formation of low efficiency 7S IgG antibody are more resistant to immunodepression. Such differences appear due to different sensitivities of cells involved in the immune response system.     

Effects of antigen-feeding on intestinal and systemic immune responses. III. Antigen-specific serum-mediated suppression of humoral antibody responses after antigen feeding.

Feeding mice sheep erythrocytes (SRBC) caused a significant decrease in splenic IgM antibody responses to SRBC given ip. Reduced IgM responses were due to a suppressor factor in the serum of fed mice rather than due to a lack of IgM antibody-forming cell precursors or to the presence of suppressor T cells. Although feeding initially primed mice to produce greater IgA and IgG anti-SRBC responses after SRBC challenge, the initial primed state was transitory. Mice fed SRBC for longer than 8 weeks had significantly reduced splenic IgG and IgA responses after SRBC challenge.Suppression of IgM responses by serum from fed mice was antigen-specific and not H-2 restricted. Serum from fed mice inhibited the induction of IgM anti-SRBC responses but did not block the expression of already established responses. The size of the suppressor factor and the ability to remove suppressor activity from serum by anti-mouse immunoglobulin suggested that suppression was mediated by antibody. However, the determinants against which the antibody was directed appeared to differ among batches of suppressor sera. Suppressor activity did not appear to be mediated by immune complexes, or soluble antigen. Oral feeding of antigen can have a marked influence on host systemic immune responses when the antigen used for feeding is subsequently administered parenterally. Thus, oral antigen administration may provide a way for specifically manipulating systemic immune responses in vivo. In addition, antigen-feeding may provide a means for producing transferable factors that suppress humoral antibody responses.     

Supressor activity of spleen cells during medically induced immunologic tolerance]

SRBC tolerance was induced in mice (CBA X C57BL/6) F1 by single intraperitoneal injection of 6 X 10(9) SRBC and of cyclophosphamide (100-200 mg/kg) in 44-46 hours. Spleen cells of tolerant mice obtained at various periods after the tolerance induction (in 12-26 days) failed to decrease their immune response to SRBC after administration to intact syngeneic recipients. Contrary to intact mice, tolerant animals were incapable of producing suppressor cells after a single SRBC immunization. Only when 3 additional injections of high SRBC doses (6 X 10(9)) were given to tolerant mice the spleen cells in them acquired the capacity to inhibit the immune response after administration to normal mice. It is supposed that the absence of suppressor cells in induction of the immunological tolerance by means of cyclophosphane was caused by the processes of clone elimination. Suppressor cells can originate in tolerant animals under the effect of intensive antigenic stimulation, this leading to enhancement of the tolerance state as a result of additional SRBC injections.     

Anti-oxidation and immune responses in mice upon exposure to manganese superoxide dismutase expressed in silkworm larvae, Bombyx mori L

With manganese superoxide dismutase expressed in silkworm larvae, Bomby mori L, we investigate the effects of silkworm larvae powder containing SOD on the antioxidation and the immune system of mouse. The contents of MDA both in mice plasma or liver organ treated with silkworm larvae powder containing manganese superoxide dismutase were reduced compare to control. The superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities both in plasma or liver organ of the treated mice were significantly higher than that of both control and bromobenzene treated mice (group-BM), suggesting the silkworm larvae powder containing SOD play a positive role in anti-oxidation in mice. This experiment was also designed to investigate the effects of silkworm larvae powder containing SOD on the immune system of mouse, focused on hemolysin response, hemagglutination against SRBC and the activity of natural killer (NK) cells. All treated mice showed significant increase in hemolysin response to SRBC and demonstrated an activation of NK cell function by the SOD-contained silkworm larvae powder, which suggest a promotion in humoral immunity. The results suggested the SOD expressed in silkworm maybe have potential application in medicine.     

Alterations in the Immunogenic Properties of Sheep Erythrocytes by Sonic Disruption

A solubilized sheep red blood cell (SRBC) antigen (supernatant fraction obtained by centrifuging 10^7-2 × 10⁸ sonicated SRBC at 6 × 10⁴ g for 30 min [Sup-SRBC]), whose ability to inhibit anti-SRBC plaque formation was 70% of that of the original sonicated SRBC, was unable to elicit a detectable antibody response in either unprimed or SRBC-primed mice. However, Sup-SRBC as well as intact SRBC antigens generated memory for the secondary response, which was transferable to irradiated syngeneic recipients by injection of immune spleen cells. The memory generated by Sup-SRBC involved helper memory for anti-trinitrophenyl group (TNP) response to challenge with TNP-conjugated SRBC. Increase in the helper T cell memory in the spleens of Sup-SRBC-primed mice was also demonstrated by an in vitro culture experiment and by an adoptive cell transfer experiment. In contrast, no detectable B cell memory was generated by Sup-SRBC. Repeated stimulation with Sup-SRBC never induced significant antibody response but reduced the level of memory. A single injection of a low dose (10⁶) of SRBC also failed to induce a definite primary antibody response generating memory for the secondary response. However, repeated stimulation with this dose of SRBC induced a high antibody response and generated good memory. From these results it is suggested that the intact structure of SRBC is required for the activation of B cells, but is not necessary for the stimulation of T cells.     

Immunomodulation by pycnogenol® in retrovirus-infected or ethanol-fed mice

Pycnogenol^® is a commercial mixture of bioflavonoids that exhibits antioxidative activity. The effects of dietary pycnogenol on immune dysfunction in normal mice as well as those fed ethanol or infected with the LP-BM5 murine retrovirus were determined. The ethanol consumption and retrovirus infection cause abnormalities in the function and/or structure of a broad array of cells involved in humoral and cellular immunity. Pycnogenol enhanced in vitro IL-2 production by mitogen-stimulated splenocytes if its production was suppressed in ethanolfed or retrovirus-infected mice. Mitogenesis of splenocytes did not show a significant change in mice treated with pycnogenol. It reduced the elevated levels of interleukin-6 produced in vitro by cells from retrovirus infected mice and IL-10 secreted by spleen cells from mice consuming ethanol. Natural killer cell cytotoxicity was increased with pycnogenol treatment.     

The effect of Bordetella pertussis lymphocytosis-promoting factor (LPF) on antibody response in mice: its enhancing and suppressive effects

The effect of lymphocytosis-promoting factor (LPF) on antibody response in mice was estimated under different sets of experimental conditions. Four- and 6-week-old mice were intravenously inoculated with LPF. Three days later these mice were inoculated either intraperitoneally or intravenously with sheep red blood cell (SRBC) or human serum albumin (HSA) as an antigen. The adjuvant effect of LPF was demonstrated on antibody response in 6-week old mice to intraperitoneally inoculated SRBC but not to intravenously-inoculated one. When 4-week-old mice were immunized, hemagglutinin production in response to intraperitoneally inoculated SRBC was not enhanced by LPF. In addition, a rather suppressive effect of LPF at a comparatively high dose was demonstrated on hemagglutinin production in response to intravenously inoculated SRBC. Anti-HSA production was enhanced by inoculation of LPF in any combination of the mouse age and the route of antigen administration. These findings indicate that the adjuvant effect of LPF on antibody response in mice depends upon experimental conditions: the age of mice, the quality of antigen and the route of antigen administration used for immunization.     

Immunosuppressive effect of Entamoeba histolytica extract on hamsters

The immune response to sheep red blood cells (SRBC) in mice and hamsters injected with an extract of entamoeba histolytica was studied. Both the primary and secondary immune response, measured by anti-SRBC antibody titers, were unaltered in the mouse, while a significant depression of the primary, but not the secondary, response was observed in the hamster. The effect was greatest when the amebic extract (AE) and SRBC were injected on the same day. The number of anti-SRBC rosettes formed in the spleen cells of hamsters treated with both AE and SRBC on day 0 was measured from days 1-16. The response peaked on day 13, while cells from animals injected with SRBC alone gave a maximal response on day 5. The formation of anti-SRBC rosettes in T-lymphocyte-enriched spleen cells treated with anti-gamma globulin serum and complement was almost abolished for the duration of the experiment. It is suggested that the mechanism responsible for this immunosuppressive phenomenon could involve early interference in the afferent limb of the immune response.     

Effect of RNA from brain of immunized mice on the specific immune response

The objective of the investigation was to study the influence of RNA isolated from the brains of immunized mice on the immune response in syngeneic recipients. (CBAxC57BL/6)F1 male mice immunized by SRBC and RRBC were used for isolation of experimental RNA. Mice injected with medium 199 were used for isolation of control RNA. Experimental and control RNA was injected into syngeneic mice recipients immunized by SRBC, RRBC or rat RBC preliminary. It was shown that experimental RNA stimulate the specific immune response only.     

Effect of allogeneic cell interaction and graft-versus-host reaction on the antibody response to Escherichia coli 0127 antigen.

The influence of allogeneic cell interaction and GVH reaction on the immune response to Escherichia coli antigen was investigated. Addition of CBA/J spleen cells to cultures of nu/nu spleen cells stimulated a significant increase in the nude PFC response to SRBC but had no significant effect on the immune response to E. coli antigen. Similarly, the induction of a GVH reaction in F₁ mice by the injection of parental spleen cells also had no significant effect on the immune response to the bacterial antigen. These results suggest that the immune response to E. coli is not affected by products of thymus-derived cells.     

Effect of trypsin on suppressor cell formation and function in localized staphylococcal infection

The present study has been made on (CBA X C57BL)F1 mice immunized with sheep red blood cells (SRBC) and inoculated with staphylococci (M-SRBC-S). The injection of splenic lymphocytes from syngeneic M-SRBC-S into intact mice has been found to suppress immune response to SRBC in these mice. The injection of trypsin into M-SRBC-S decreases the suppressive action of their lymphocytes on SRBC-induced immune response in syngeneic recipients. The injection of trypsin into the recipients has been found to produce no effect on the immunosuppressive action of transplanted lymphocytes obtained from M-SRBC-S. The injection of trypsin into M-SRBC-S induces the release of the factor, inhibiting the formation and function of suppressor cells, by their splenocytes. Previously formed suppressor cells block the release of the immunostimulating factor by the splenocytes of the animals receiving the injections of trypsin.     

Antigen-specific helper activity in serum of mice primed with sheep red cells. I. Definition of the test system and comparison with other systems

An adoptive transfer system is described to measure serum helper activity in the primary antibody response to sheep red blood cells (SRBC). Mice injected with a high dose of cyclophosphamide and reconstituted with rabbit anti-thymocyte serum-treated spleen cells were used as recipients. Serum obtained 9 hr after ip injection of normal mice with 2 × 10⁸ SRBC (S(SRBC)) injected i.v. in the recipients caused a significant enhancement of the antibody response to 2 × 10⁷ SRBC. The serum helper activity was not generated in thymectomized animals and could be absorbed from S(SRBC) by normal and formalinized SRBC. The SRBC-specific serum helper activity (SSHA) is heat labile (30 min 56 °C) and shows allogeneic restriction. Another test system described in literature for measuring T-cell help in vivo was less suited to measure SSHA in the response to 2 × 10⁷ SRBC. A system using normal mice injected with 10⁵ SRBC for determining specific immune response-enhancing factor (SIREF), demonstrated SIREF activity in S(SRBC). It did, however, not measure SSHA, as absorption of S(SRBC) with formalinized SRBC did not abolish the activity in that system.     

Characteristics of the reaction of immunologically tolerant mice to the polyclonal stimulant salmozan

The nonspecific stimulant of the immune response salmozan (Sal) increases the number of PFC against SRBC in intact mice, B mice (thymectomized, irradiated and reconstituted with embryonic liver cells), and in mice pretreated with cyclophosphamide (CY). This effect was decreased in mice pretreated with SRBC and CY. The subsequent injections of SRBC and Sal into tolerant mice did not increase the response under study. It is concluded that the effect observed is due to partial alteration of antigen-specific B cells of tolerant mice and this alteration cannot be explained by the lack of the regeneration of membrane immunoglobulins.     

Murine bone marrow IgA responses to orally administered sheep erythrocytes

Specific immunization protocols have been established for the induction of murine bone marrow IgA responses to the T cell-dependent (TD) antigen sheep red blood cells (SRBC). Systemic immunization, either i.p. or i.v., followed by a second injection, induced splenic IgM and IgG responses and a bone marrow IgM response. No significant IgA responses were observed in either lymphoid tissue compartment. Oral immunization with SRBC by gastric intubation for 2 days, followed 1 wk later by an i.p. injection of SRBC resulted in a splenic IgA plaque-forming cell (PFC) response, but did not elicit a bone marrow IgA response. Repeated daily gastric intubation of SRBC to C3H/HeN and C3H/HeJ mice led to the previously reported pattern of systemic unresponsiveness in C3H/HeN mice and good anamnestic type IgM, IgG, and IgA splenic anti-SRBC PFC responses in the C3H/HeJ strain upon parenteral challenge. Oral administration of SRBC for 14 days to C3H/HeN mice, followed by systemic SRBC challenge, resulted in diminished splenic PFC responses of all isotypes, whereas gastric intubation of SRBC for 28 days led to complete systemic unresponsiveness to antigen in C3H/HeN mice. Interestingly, the repeated oral administration of SRBC resulted in significant bone marrow IgA PFC responses upon i.p. challenge in both C3H/HeN and C3H/HeJ mouse strains. The bone marrow IgA responses were clearly dependent upon chronic oral exposure to SRBC, because gastric intubation with SRBC for 2 consecutive days/wk for 10 wk also induced bone marrow and splenic IgA anti-SRBC PFC responses in C3H/HeN mice. These results suggest that memory B cells reside in the bone marrow of orally immunized mice and can yield anamnestic-type responses to challenge with the inducing antigen. The memory cells may arise in the Peyer's patches of the gut and migrate to the bone marrow. The possibility that the bone marrow is a component of the common mucosal immune system in mammals is suggested by this study.     

The influence of phase shift in the light-dark cycle on humoral immune responses of mice to sheep red blood cells and polyvinylpyrrolidone

The influence of a phase shift in the light-dark cycle on humoral immune responses against sheep red blood cells (SRBC), a thymus-dependent antigen, and against polyvinylpyrrolidone (PVP), a thymus-independent antigen, was studied by using 180 BALB/c mice and 150 C3H/HeN mice. Significant suppression of the immune response to SRBC and the number of splenic plaque-forming cells (PFC) and hemagglutination (HA) titers was observed on days 5 and 6 after inversion of the light-dark cycle. On the other hand, the number of splenic PFC and HA titers in the blood against PVP were minimally suppressed by the phase shift in C3H/HeN mice, except for distortion of the rhythmicity. Corticosterone levels in the blood on days 5 and 6 after inversion were higher than those under a normal lighting regimen. The appearance of the high corticosterone level in the blood after the inversion almost concurred with the suppression of the immune response to SRBC. A decrease of the proportion of splenic T cells was also observed on day 6 after the inversion. These results show that a phase shift in the light-dark cycle provokes suppression of the immune response to SRBC, possibly through an increase of secretion of corticosterone after light-dark inversion, which induces a decrease of the proportion of T lymphocytes in the spleen.