Influence of the maternal effect on allogenic inhibition of hematopoietic stem cells]

Bone marrow cells (0,5-10(6)) of female mice of CBA or C57BL strains were injected intravenously to lethally irradiated CBA, C57BL/6, (femaleCBA X maleC57BL/6)F1 and (femaleC57BL/6 X maleCBA)F1 mice. Spleen of recipients as assayed for colony count on the 9th day after bone marrow transplantation by the method of Till and McCullouch. Stem cells of CBA mice demonstrated failure of allogenic inhibition in (CBA X C57BL/6)F1 hybrid mice and formed the same number of colonies as in the spleen of syngenic recipients. The level of allogenic inhibition of CBA stem cells transplanted to (C57BL/6 X X CBA)F1 hybrid mice was 50%. Bone marrow cells of C57BL/6 mice formed colonies in spleen of (CBA X C57BL/6)F1 mice at least in 20 times less than in syngenic combination. In the transplantation of bone marrow from C57BL/6 mice to (C57BL/6 X CBA)F1 hybrid mice the allogenic inhibition was less pronounced (77-85%) as compared with the transfer of cells to (CBA X C57BL/6)F1 hybrid mice (95%). The sex of a recipient did not influence the number of formed colonies. The different level of allogenic inhibition of parental stem cells can not be explained by the effect of linkage with sex as the female of reciprocal hybrid mice have identical structure of sex chromosomes (X(CBA)XC57BL/6). The data obtained indicate that the maternal effect affects allogenic inhibition of stem cells in parent--F1 system. It is possible that the maternal influence may be determined by cytoplasmic factors of inheritance which affect the expressivity of recessive genes Hh, controlling the inheritance of specific haematopoietic cell antigens.     

Immune responses of different mouse strains after challenge with equivalent lethal doses of Toxoplasma gondii

Most immunological studies that utilize different strains of inbred mice following T. gondii infection fail to compensate for differences in host susceptibility to the size of the parasite innoculum. To address this concern, susceptible C57BL/6 and resistant CBA/J mice were orally infected with either an equivalent 50% lethal dose (LD50) of brain cysts of the 76K strain of T. gondii (15 cysts in C57BL/6, 400 cysts in CBA/J) or the same dose of parasites in each mouse strain. C57BL/6 mice receiving 400 cysts (LD50 of CBA/J mice) died post infection, whereas CBA/J mice that received 15 cysts (LD50 of C57BL/6 mice) survived. Parasite loads in the brains and serum Toxoplasma-specific IgG1 titers of LD50-infected C57BL/6 mice were significantly higher than those in LD50- or 15 cysts-infected CBA/J mice, whereas splenocyte proliferation to Toxoplasma antigen and the percentage of CD8 alpha+ T cells were reduced in LD50-infected C57BL/6 mice. In contrast, serum IgG2a and IgM titers, the percentage of gamma delta T cells and IFN-gamma expression of spleen of LD50-infected CBA/J mice were higher than those of either 15 cysts-infected CBA/J mice or LD50-infected C57BL/6 mice. These observations demonstrate that the immune response between LD50-infected C57BL/6 and CBA/J mice was more prominent when compared to C57BL/6 or CBA/J mice receiving the same parasite inoculum. These observations would suggest that caution must be excersized in the planning and interpretation of data when the size of the parasite inoculum has not been adjusted for mouse strain.     

Comparative study of the phagocytosis of sheep erythrocytes by the macrophages of inbred mice differing in their sensitivity to immunogenic stimulation by the given antigen

The phagocytosis of 14C-labeled sheep red blood cells (SRBC) by the macrophages of isogeneic CBA, BALB/c and C57BL/6 mice was studied. In the presence of bovine serum the macrophages of CBA mice were found to ingest SRBC significantly less actively than the macrophages of BALB/c and C57BL/6 mice. In the presence of isologous serum the macrophages of mice belonging to the strains under study showed quite comparable characteristics with respect to their capacity of ingesting SRBC. The duration of the intracellular digestion of SRBC by the macrophages of mice of these strains did not vary in different strains irrespective of the type of serum.     

Inhibition of the graft-versus-host response by BCGcw-induced suppressor cells or prostaglandin E1

Immunization of C57BL/6 mice with BCGcw stimulated a population of "suppressor cells" which had a decreased capacity to induce the graft-versus-host response. The graft-versus-host response was quantitated using the Simonsen splenomegaly assay. F1 mice (C57BL/6 X CBA) were inoculated intraperitoneally with 1 X 10(8) parental (C57BL/6) or (CBA) spleen cells. The F1 mice were sacrificed 13 days later and the resulting splenomegaly was 3-4 times the normal amount. F1 mice which were injected with parental BCGcw-primed C57BL/6 spleen cells had a 50% inhibition of splenomegaly, whereas BCGcw-primed CBA spleen cells (a strain which does not develop suppressor cells) did not show this inhibition. In vitro results also confirmed that only C57BL/6 mice and not CBA mice developed suppressor cells after BCGcw immunization. A second study showed that X-irradiated (1000 R) BCGcw-primed "suppressor cells" could inhibit splenomegaly caused by the inoculation of normal parental C57BL/6 cells into F1 mice. The mechanism by which BCGcw-primed "suppressor cells" caused this inhibition of splenomegaly was delineated and found to be dependent upon the secretion of prostaglandin (PGE-1). Indomethacin and aspirin, potent inhibitors of prostaglandin synthesis, blocked the activity of C57BL/6 BCGcw "suppressor cells" and splenomegaly resulted. Systemic administration of the prostaglandin (15S)-15-methyl PGE-1 reduced splenomegaly approximately 50% in F1 mice which were injected with C57BL/6 or CBA cells. These results indicated that immunization with BCGcw stimulated a population of "suppressor cells" which could cause a decrease in graft-versus-host response and that the secretion of prostaglandin was responsible for this inhibition.     

Effect of prodigiosin and its combination with immunodepressants on the graft versus host reaction in mice

The local (lymph node) graft-versus-host reaction (GVHR) in F1 (CBA X C57BL/6) mice and the lethal GVHR in C57BL/6 mice were induced by transfer of lymph node cells of CBA mice with skin allotransplants from C57BL/6 mice. Prednisolone in combination with asathioprin (imuran) administered to CBA mice inhibited the GVHR. Prodigiosan used alone was not active, while in combination with immunodepressants it increased their inhibitory effect. Adhesive cells with a suppressive activity were detected in the spleen of mice treated with prodigiosan. Such cells were capable of suppressing the capacity of syngeneic lymphocytes for inducing the GVHR.     

Chimeric drift in allophenic mice.

The composition of the immune system of 33 allophenic mice of four different types [C57BL/6 in equilibrium DBA/1, C57BL/6 in equilibrium (CBA X CBA/H-T6), C57BL/6 in equilibrium (A X SJL), DBA/1 in equilibrium (CBA X CBA/H-T6)] was studied. It was found that the parental composition of the peripheral white blood cells changed significantly during a two-month interval in 11/33 or 33% of the mice studied. This phenomenon has been termed chimeric drift. The animals were sacrificed between 9 and 16 months of age, and the parental composition of the peripheral white blood cells, spleen white blood cells, and thymocytes was determined on the day of sacrifice. It was foound that the peripheral white blood cell and spleen white blood cell compositions showed a high degree of correlation. However 8/33 or 24% of the mice studied showed discordance of the spleen and thymocyte cell populations. Seven of the 8 mice which showed spleen-thymocyte discordance, had also shown evidence of chimeric drift earlier in their lives. We suggest that this is evidence that chimeric drift may have an immunological basis.     

Production of a factor inhibiting macrophage migration to the Candida albicans antigen in mice and their resistance to this microorganism

Resistance to C. albicans, an opportunistic microorganism, has been studied in CBA and C57BL/6 mice, oppositely responsive in the production of the factor inhibiting migration of macrophages to antigen obtained from this fungus. The study has shown that CBA mice, highly responsive in the macrophage migration inhibiting factor, are less resistant to C. albicans, while C57BL/6 mice with low response to this antigen are more resistant to this infective agent. Macrophages play, probably, a certain role in the generalization of the process because not all phagocytized C. albicans cells are digested.     

Interstrain differences in mice in developing migration inhibition factors to Candida albicans antigens

The authors studied the time course of MIF production by lymphocytes of CBA (H-2k), C57BL/6J (H-2b) and (CBA X C57BL/6J) F1 (H-2b/H-2k) mice sensitized to Candida albicans antigens. The interstrain differences in lymphokin production were identified, CBA mice appeared to be highly responsive, whereas C57BL/6J to be low-responsive. Partial hybridological analysis made it possible to ascertain the presence of the dominant type heredity of high MIF production in response to Candida albicans antigens.     

Genetic control of allogenic inhibition of hematopoietic stem cells]

Adult mice of C57BL/6, CBA (CBA X C57BL/6) F1, (CBA X C57BL/6) F2, F1 X CBA and F1 X C57BL/6 strains were lethally irradiated and reconstituted with a constant dose of 3-10(5) C57BL/6 bone marrow cells. At the 9th day after the bone marrow transplantation the colony count was performed in spleen of irradiated recipients. In the spleen of F1, CBA and C57BL/6 mice were registered low (0--8, intermediate (6--18) and high (22-40) numbers of colonies respectively. The segregation ratios in F2 progeny were close to 2 (low): 1(intermediate): 1(high). The segregation ratios in backcross (F1 X CBA) were close to 1(low): 1(intermediate)numbers of colonies. Backcrosses (F1 X C57BL/6) were distributed to low and high numbers of colonies with the ratio 1:1. The number of spleen colonies of males and females was the same in all segregating progeny. The results of hybrid analysis suggest that a single pair of allelic genes is involved in genetic control of allogenic inhibition, and that the resistance (manifestation of inhibition) to C57BL/6 stem cells is conferred by the dominant allele.     

The effect of aging on the induction of humoral and cellular immunity and tolerance in two long-lived mouse strains.

Aging is a complex process that adversely affects most if not all components of the immune system. In this report, two long-lived mouse strains have been compared in ability to generate both antigen-specific immunity and tolerance. Although CBA/CaJ mice produced high levels of antibody following injection of aqueous preparations of aggregated human gamma-globulin (AHGG), C57BL/6 mice made only meager antibody responses to such preparations. Age dramatically affects the humoral anti-HGG response to aqueous AHGG in both strains, but the meager response of young C57BL/6 mice was at insignificant levels in aged C57BL/6 mice. Conversely, both mouse strains generated good responses following injection of HGG in complete Freund's adjuvant at both the T and B cell level as evidenced by in vitro antigen-specific T cell proliferation and anti-HGG antibody production. Aged mice of both strains showed a marked decrease in the production of serum anti-HGG antibody in comparison to young mice. Although the antigen-specific T cell proliferative response was significantly decreased in aged CBA/CaJ mice, such proliferation was not affected in aged mice of the C57BL/6 strain. Removal of CD8+ cells from lymph node T cells of either young or aged C57BL/6 mice did not increase the antigen-specific proliferative response, suggesting that loss of CD8+ suppressors during the aging process is not responsible for the high level of antigen-specific T cell proliferation in aged C57BL/6 mice. Tolerance to HGG was readily induced in both young and aged C57BL/6 and CBA/CaJ mice although aged mice demonstrate a modest resistance to tolerance induction when compared to their young counterparts. This resistance was observed in both antibody production and antigen-specific T cell proliferation.     

Comparison of heterogeneities of antitrinitrophenyl antibodies in strains of mice immunized by various methods.

Heterogeneity of antibodies directed against the trinitrophenyl (TNP) determinant in immunized mice was analyzed by investigating the band groups of antibodies formed by thin layer isoelectric focusing of serum. The degree of heterogeneity in C57BL/6 mice was markedly higher than that in CBA mice under the following conditions of immunization: immunization with TNP conjugated with bovine gamma-globulin or ovalbumin, interchange of these carrier proteins at the first and second injections, change of epitope density of the antigens, replacement of the hapten by dinitrophenyl group on the antigen for the secondary stimulation, and change of intervals of these injections from 15 days to five months. The degree of heterogeneity within a strain also varied with these immunizing conditions. Furthermore, the heterogeneity in C57BL/6 mice of any immunization group was greater than that in CBA mice in any group. This was also true when the heterogeneity was examined with the immune sera diluted to the same titer. These results indicate that the number of predominant clones of cells producing anti-TNP antibody after immunization is larger in C57BL/6 than in CBA mice.     

Effect of genotype on the development of aggressive and submissive behavior in the mouse

Aggressive and submissive behaviour was studied in CBA/Lac and C57BL/6J strains of mice during long-term intermale interaction with syngenic partners. It was shown that the aggressiveness of aggressive C57BL/6J animals was more expressive than that of CBA/Lac' ones. The structure of submissive behaviour of this strains' encounters was also significantly different. Prolonged-defeat experience changed the character of submissive behaviour of C57BL/6J, but not of CBA/Lac' ones. Aggression of dominant animals considerably decreased in both strains. It is suggested that CBA/Lac and C57BL/6J mice had different mechanisms of suppression of intermale aggression.     

Comparative characteristics of the parameters of an aggressive reaction in 2 mouse genotypes

The parameters have been studied of the aggressive reaction of male mice of CBA/Lac and C57BL/6J lines differing by olfactory sensitivity to zoosocial pheromone stimuli. It has been shown that CBA males, characterized by a high olfactory sensitivity, have lower latency of the first attack than C57BL males with low olfactory sensitivity. A prolonged distant exposition to an unknown litter and male appearance lowers the latency of the first attack in mice of the studied lines proportionally to their meanings demonstrated after short time exposition. The number of attacks and total time of attacking is considerably higher in C57BL mice during the whole test period (15 min) than in CBA mice in which aggressivity is already sharply lowered after 5 min of agonistic interactions. The factors are discussed, influencing the parameters of mice aggressive reaction.     

Radiation-induced pulmonary endothelial dysfunction and hydroxyproline accumulation in four strains of mice

C57BL mice exposed to 14 Gy of whole-thorax irradiation develop significant histologic lung fibrosis within 52 weeks, whereas CBA and C3H mice do not exhibit substantial fibrosis during this time. The purpose of the present study was to determine whether this strain-dependent difference in radiation histopathology is associated with genetic differences in pulmonary endothelial metabolic activity or in endothelial radioresponsiveness. C57BL/6J, C57BL/10J, CBA/J, and C3H/HeJ mice were sacrificed 12 weeks after exposure to 0 or 14 Gy of 300-kV X rays to the whole thorax. Lung angiotensin converting enzyme (ACE) activity and plasminogen activator (PLA) activity were measured as indices of pulmonary endothelial function; and lung hydroxyproline (HP) content served as an index of pulmonary fibrosis. Lung ACE and PLA activities in sham-irradiated C57BL/6J and CB57BL/10J mice were only half as high as those in sham-irradiated CBA/J and C3H/HeJ mice. Exposure to 14 Gy of X rays produced a slight but nonsignificant reduction in lung ACE and PLA activity in the C57BL strains, and a significant reduction in the CBA/J and C3H/HeJ mice. Even after 14 Gy, however, lung ACE and PLA activities in CBA/J and C3H/HeJ mice were higher than those in sham-irradiated C57BL/6J and C57BL/10J mice. Lung HP content in all four strains increased significantly after irradiation, but this increase was accompanied by an increase in lung wet weight. As a result, HP concentration (per milligram wet weight) remained constant or increased slightly in both C57BL strains and actually decreased in the CBA/J and C3H/HeJ mice. These data demonstrate significant genetic differences in both intrinsic pulmonary endothelial enzyme activity and endothelial radioresponsiveness among the four strains of mice. Specifically, strains prone to radiation-induced pulmonary fibrosis (C57BL/6J, C57BL/10J) exhibit only half as much lung ACE and PLA activity as do strains resistant to fibrosis (CBA and C3H).     

TGF-beta and IL-10 regulation of IFN-gamma produced in Th2-type schistosome granulomas requires IL-12

Interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) regulate CD4+ T cell interferon-gamma (IFN-gamma) secretion in schistosome granulomas. The role of IL-12 was determined using C57BL/6 and CBA mice. C57BL/6 IL-4-/- granuloma cells were stimulated to produce IFN-gamma when cultured with IL-10 or TGF-beta neutralizing monoclonal antibody. In comparison, C57BL/6 wild-type (WT) control granuloma cells produced less IFN-gamma. IL-12, IL-18, and soluble egg antigen stimulated IFN-gamma release from C57BL/6 IL-4-/- and WT mice. IFN-gamma production in C57 IL-4-/- and WT granulomas was IL-12 dependent, because IL-12 blockade partly abrogated IFN-gamma secretion after stimulation. All granuloma cells released IL-12 (p70 and p40), and IL-12 production remained constant after anti-TGF-beta, anti-IL-10, recombinant IL-18, or antigen stimulation. C57 WT and IL-4-/- mouse granuloma cells expressed IL-12 receptor (IL-12R) beta1-subunit mRNA but little beta2 mRNA. TGF-beta or IL-10 blockade did not influence beta1 or beta2 mRNA expression. CBA mouse dispersed granuloma cells released no measurable IFN-gamma, produced IL-12 p70 and little p40, and expressed IL-12R beta2 and little beta1 mRNA. In T helper 2 (Th2) granulomas of C57BL/6 WT and IL-4-/- mice, cells produce IL-12 (for IFN-gamma production) and IL-10 and TGF-beta modulate IFN-gamma secretion via mechanisms independent of IL-12 and IL-12R mRNA regulation. We found substantial differences in control of granuloma IFN-gamma production and IL-12 circuitry in C57BL/6 and CBA mice.     

The effects of selective immunosuppression on resistance to Mesocestoides corti in strains of mice showing high and low initial susceptibility

Previous work has shown that C57BL/6 mice had the lowest initial susceptibility to Mesocestoides corti of six strains of mice examined. Parasite burdens in this strain and in CBA/H mice, a strain showing a higher initial susceptibility to M. corti, were compared following selective immunosuppressive treatments. Irradiation, splenectomy and the administration of cyclophosphamide and methyl prednisolone all resulted in higher parasite burdens in C57BL/6 mice. In contrast these treatments had a minimal effect on parasite burdens in CBA/H mice. In the light of these results the role of antibody in controlling parasite proliferation is discussed.     

Effect of syngenic lymphocytes on allogenic inhibition of hematopoietic stem cells of embryonic liver]

The transplantation of liver from the embryos and newborn C57BL-6 mice to the lethally irradiated hybrids (CBA X C57BL/6) F1resulted in 90% allogenic inhibition of the colony-forming activity of the donor elements. The degree of allogenic inhibition of liver cells of 19 days old embryos and newborn mice may be changed with the help of syngenic lymphocytes of adult mice or delayed transplantation of cells 72 hrs following the irradiation of recipients but these procedures proved to be ineffective with the liver cells of 13 and 16 days old embryos. A suggestion is put forward to the effect that the allogenic inhibition is based on the active reaction of recipient hybrids (CBAXXC57BL/6) F1 to the stem hemopoietic cells of C57BL/6 mice.     

Exploratory activity of mice of different genetic strains after olfaction disruption by 3-methylindole (skatole)

The behavior of mice of two inbred strains (C57BL/6J and CBA) and their F1 hybrids was evaluated in the open field test after intraperitoneal administration of 3-methylindole (skatole) disrupting epithelium of the main olfactory system. High motor and exploratory activities and emotional sensitivity was observed in intact C57BL/6J mice compared to CBA mice and their hybrids. Anosmia induced by intraperitoneal administration of skatole changed the behavior of C57BL/6J and CBA mice. The direction of the observed changes in the orientation and exploratory behavior of anosmic animals was different. Anosmia decreased motor and exploratory activities in C57BL/6J mice and increase them in CBA mice. Intact hybrid mice demonstrated the predominance of the CBA genotype in the orientation and exploratory activity in the test used. Anosmia in hybrid animals had no significant effect on the orientation and exploratory behavior.     

Genetics of the anti-dextran B512 and the autoanti-idiotypic response: codominant expression in F1 hybrids and dichotomy of response and allotype-linked idiotype

The IgM plaque-forming response to the alpha 1-6 epitope of dextran B512 is linked to the Ig-1 heavy chain allotypes j and b characteristic of CBA and C57BL strains, respectively, and the response typically induces the formation of autoanti-idiotypic antibodies that can distinguish between anti-dextran antibodies of CBA and C57BL origin. Nevertheless, some substrains of Balb/c mice (allotype a) and some Bailey recombinant stains give a PFC response although they do not possess allotypes j or b. The anti-dextran antibodies in these strains lack the idiotypes characteristic of either CBA and C57BL antibodies to dextran, but they possess their own particular idiotype. F1 hybrids between two responder strains possessing different idiotypes on their antibodies against dextran, produce both idiotypes and two different autoanti-idiotypic antibodies. CBA(Ig-1b) mice were high responders to dextran and possessed the idiotype of C57BL, whereas C57BL/6(Ig-1a) mice were low responders. The V(H) recombinant strains BAB.14 and CB-8KN that possess the Ig-1b allotype of C57BL, but have some of the V(H) genes from Balb/c and the rest from C57BL/6 were high responders to dextran, but did not possess the C57BL idiotype, suggesting that the genes determining the response against dextran and the idiotype may have different locations in the heavy chain locus.     

Increased Intestinal Epithelial Cell Turnover and Intestinal Motility in Gymnophalloides seoi-Infected C57BL/6 Mice

The changing patterns of goblet cell hyperplasia, intestinal epithelial cell turnover, and intestinal motility were studied in ICR and C57BL/6 mice infected with Gymnophalloides seoi (Digenea: Gymnophallidae). Whereas ICR mice retained G. seoi worms until day 7 post-infection (PI), C57BL/6 mice showed a rapid worm expulsion within day 3 PI. Immunosuppression with Depo-Medrol significantly delayed the worm expulsion in C57BL/6 mice. Goblet cell counts were increased in both strains of mice, peaking at day 1 PI in C57BL/6 mice and slowly increasing until day 7 PI in ICR mice. In C57BL/6 mice infected with G. seoi, newly proliferating intestinal epithelial cells were remarkably increased in the crypt, and the increase was the highest at day 1 PI. However, in ICR mice, newly proliferating intestinal epithelial cells increased slowly from day 1 to day 7 PI. Intestinal motility was increased in G. seoi-infected mice, and its chronological pattern was highly correlated with the worm load in both strains of mice. Meanwhile, immunosuppression of C57BL/6 mice abrogated the goblet cell proliferation, reduced the epithelial cell proliferation, and suppressed the intestinal motility. Goblet cell hyperplasia, increased intestinal epithelial cell turnover, and increased intestinal motility should be important mucosal defense mechanisms in G. seoi-infected C57BL/6 mice.