Genetic control of resistance to murine malaria

Strain variation in the level of resistance to malaria was investigated in inbred mice after infection with Plasmodium chabaudi. Following intraperitoneal infection with the typing dose of parasitized erythrocytes, mice of 11 inbred strains could be separated using survival time as the criterium into resistant and susceptible groups. Genetic analysis of F₁ hybrid and backcross progeny derived from one of the most resistant (B10.A) and from the most susceptible (A/J) strains as parents suggested that host resistance in this strain combination was genetically controlled by a dominant, non-H-2-linked, autosomal gene or closely linked genes. Analysis of the mechanisms of resistance to P chabaudi showed (1) phenotypic expression of the resistance gene was apparent within 6 days of infection as a significant difference between resistant and susceptible mice in the level of parasitemia; (2) the level of host NK cell activity was not related to the level of host resistance to malaria; (3) compared with susceptible A/J mice, resistant B1O.A hosts had an augmented erythropoietic response during the course of malaria as well as during phenylhydrazine-induced anemia and (4) treatment with BCG or P acnes resulted in an equal degree of protection, measured by parasitemia and survival, in both resistant and susceptible mice.     

Hybrid resistance to BALB/c plasmacytomas. I. Resistance to MPC-11 controlled by a locus not linked to H-2.

Genetic control of hybrid resistance to the BALB/c plasmacytoma MPC-11 was investigated. The results indicate that a single dominant autosomal gene or gene complex, which segregates independently of H-2 and the coat color c and b-loci, controls resistance to this tumor. This gene has the same strain distribution pattern in the CXB Bailey recombinant inbred strains as three unlinked genes, H-2, Ly-4, and Ea-4. It is possible, therefore, that it could be linked to either of the latter two loci. Strains that carry a positive allele for resistance are C57BL/10 and all of its congenic resistant partners tested, C57BL/6, C57L, C57BL/Ks, AKR, and DBA/1. BALB/c and its congenic resistant partners are presumed to carry a negative allele of the gene for resistance to MPC-11. Strains such as SJL, DBA/2, and A and its congenic resistant partners, which form susceptible hybrids with BALB/c, could carry either the negative allele of the gene for resistance, like BALB/c, or could carry both a positive allele of the gene and some other gene conferring susceptibility on the hybrids. Heterozygosity within the H-2 complex increases resistance only in the presence of this non-H-2 linked gene for resistance, and the effect maps to the left of the H-2D region.     

The genetic control of natural killer cell activity and its association with in vivo resistance against a moloney lymphoma isograft

Spleens of normal young mice of certain strains contain lymphocytes that can kill strain A-derived YAC-1 lymphoma cells in a⁵¹Cr release cytotoxic assay in vitro. We have previously classified mouse genotypes as high or low reactors, according to their responses in this test. In vivo resistance to small numbers of YAC ascites lymphoma cells is correlated with in vitro cytolytic activity. In vitro and in vivo tests were carried out on the same individual (A x C57BL)F₁ x A backcross mice. Natural in vitro killer cell activity appeared to be under polygenic control, including a strong H-2-linked factor. No linkage was found with five different isozyme loci, with theIg-l locus or with C5 serum activity. Also in vivo resistance showed strong linkage with theH-2 complex. In (A x CBA)F₁ x A backcross mice, a weak linkage was found with the coat color locusC. There was a correlation between in vitro killer activity and in vivo resistance in the same backcross mice. In vivo resistance was particularly strong in mice that combined theH-2 ^b -linked resistance factor with a high cytolytic activity in vitro.     

Semisyngeneic hybrid resistance to murine teratocarcinoma cells

Resistance to two cultured lines of murine embryonal carcinoma was studied in F1 hybrids constructed between the tumor-syngeneic mouse strain 129/J and several allogeneic strains. Three of four such hybrid strains were significantly more resistant to the multipotent embryonal carcinoma line PCC3 than the tumor-syngeneic 129/J parent strain. All hybrid strains tested showed significantly higher resistance to the nullipotent embryonal carcinoma line F9 than the syngeneic strain. Hybrid resistance to embryonal carcinoma lines does not require a hybrid H-2 complex. Several kinds of evidence indicate that this hybrid resistance has an immunological basis.     

Induction and selection of formaldehyde-based resistance inPseudomonas aeruginosa

Summary A formaldehyde resistant (R) phenotype ofPseudomonas aeruginosa was isolated from a formaldehydesensitive (S) parent by sequential treatment with 1,3,5-tris-(ethyl)hexahydro-s-triazine (ET). The resistance of the (R) strain to treatment with ET was approximately 3-fold higher than the parental (S) strain. Two modes of resistance to ET, and simultaneous resistance to formaldehyde, are demonstrated: (1) transient or induced resistance is expressed during shor-term exposure to ET, and this resistance is gradually lost during subsequent growth in the absence of ET, and (2) resistance that results from a stable phenotypic change in the (S) strain following sequential treatment with ET ((R) strain phenotype). The observed activities of three forms of the formaldehyde oxidizing enzyme, formaldehyde dehydrogenase, are strongly correlated with the relative response of the (S) and (R) strains to treatment with ET. The observed resistance of the (R) strain appears to be due to high levels of an NAD⁺-linked, glutathione-dependent form of formaldehyde dehydrogenase as well as a dye-linked formaldehyde dehydrogenase. The transient or induced response of the (R) strain involves an increase in activity of the dye-linked formaldehyde dehydrogenase. The induced response of the (S) strain and an ATCC strain ofP. aeruginosa, however, is correlated with the two forms of the NAD⁺-linked enzyme (glutathione-dependent (EC 1.2.1.1) and independent (EC 1.2.1.46)) with no contribution from the dye-linked enzyme.     

Genetically determined resistance to murine cytomegalovirus and herpes simplex virus in newborn mice.

Mice which were infected with the herpesvirus murine cytomegalovirus or herpes simplex virus type 1 on the day of birth exhibited mouse strain-dependent differences in the development of lethal disease. The pattern of resistance among the strains was distinct for each virus and closely resembled that reported in adult mice. However, much lower doses of the viruses were required in newborn mice to reveal these resistance patterns. For murine cytomegalovirus, both H-2-associated and non-H-2 genes conferred resistance, and, as has been shown for adults, there was a 25-fold difference in the dose required to kill 50% of the animals belonging to the most resistant and susceptible strains. The resistance of newborn mice to herpes simplex virus type 1 was conferred by non-H-2 genes in C57BL/6 mice, as has been reported for adults, and newborn C57BL/6 mice were considerably more resistant than mice of susceptible strains. Resistance was also reflected in the titer of these viruses in the spleen or liver early in infection and, with murine cytomegalovirus, in the survival time of infected mice. The resistance of newborn mice to lethal disease was not conferred postnatally by the mother. This appears to be the first report of genetically determined resistance to herpesviruses in newborn mice. Such autonomous virus-specific resistance may provide a significant barrier to naturally acquired infection in genetically resistant strains. Similar genetically regulated mechanisms may protect the newborns of many species, including humans, against infection with herpesviruses.     

Genetically determined resistance to mouse hepatitis virus 3 is expressed in hematopoietic donor cells in radiation chimeras

Differences in mouse hepatitis virus 3 (MHV3) sensitivity among mouse strains are mainly determined by H-2-related and -nonrelated genetic factors. Reciprocal chimerism was therefore established between two H-2a compatible pairs of strains that differ widely in their susceptibility to MHV3: a) A/J and B10.A, respectively resistant and highly susceptible; b) A/J and A/Sn, respectively resistant and semisusceptible. Chimeric mice were challenged with 100 LD50 of MHV3, 30 or 90 days after X-irradiation (900 R) and bone marrow reconstitution. Results showed that sensitivity of recipients was similar either to that of the recipient strain or to that of the donor strain when chimeric mice were tested 30 or 90 days, respectively, after reconstitution. In addition, no paralysis occurred in surviving animals. These data indicate, therefore, that resistance or susceptibility to MHV3 is expressed intrinsically in some population(s) of hematopoietic-derived cells, which is radioresistant and has a life span of more than 30 days and less than 90 days. Additional experiments showed that X-irradiated A/J recipients reconstituted with A/J bone-marrow cells were protected against MHV3 challenge with spleen cells, with a mixture of spleen cell populations or of adherent spleen cells and thymocytes originating from A/J donors. Transfer of protection to recipients by using similar cell populations provided by semisusceptible A/Sn donors required the administration of five times more cells. Results suggest that two complementary mechanisms are required to confer resistance to MHV3: a) a gene(s) for resistance that may operate at the level of macrophages, and b) cells capable of mounting an efficient immune response. The reduced efficiency of A/Sn spleen cells suggests that semisusceptibility to MHV3 may be related to partial quantitative or functional immune defect.     

Semisyngeneic hybrid resistance to murine teratocarcinoma cells

Resistance to two cultured lines of murine embryonal carcinoma was studied in F₁ hybrids constructed between the tumor-syngeneic mouse strain 129/J and several allogeneic strains. Three of four such hybrid strains were significantly more resistant to the multipotent embryonal carcinoma line PCC3 than the tumor-syngeneic 129/J parent strain. All hybrid strains tested showed significantly higher resistance to the nullipotent embryonal carcinoma line F9 than the syngeneic strain.Hybrid resistance to embryonal carcinoma lines does not require a hybridH-2 complex.Several kinds of evidence indicate that this hybrid resistance has an immunological basis.     

Single gene control of resistance to cutaneous leishmaniasis in mice

A series of inbred, congenic resistant, and hybrid strains of mice were intradermally inoculated with 10⁶ promastigotes of Leishmania tropica. These mice were divided into susceptible and resistant groups using the criteria of lesion size, development of metastatic foci and skin-test reactivity. At 16 weeks of infection, resistant strains A/J, DBA/1J, AKR/J, CBA/J, C3H/HeJ, NZB/BINJ, C57BL/6J, C57BL/10Sn, B10.D2, B10.129(10M), and B10.CE(30NX) had completely resolved their lesions, while susceptible SWR/J and BALB/cJ mice demonstrated large, nonhealing cutaneous lesions. In addition, BALB/cJ developed metastatic lesions on the extremities which progressively increased in size. All BALB/cJ and SWR/J mice died by 7 1/2 months of infection. The BALB/cJ x C57BL/6JF₁ hybrid behaved in an intermediate fashion showing a slower expansion of cutaneous ulcers and a delayed development of metastatic foci, however, the infection ultimately proved fatal. The F₂ generation could be separated into three distinct groups: resistant, intermediate, and susceptible mice with a lesion size distribution pattern in conformity with a 1:2:1 ratio. Male/female susceptibility differences were not noted. These data indicated that development of acquired resistance may be under the control of a single, autosomal gene. The gene did not appear to be H-2-, Ir-2-, or H-11-linked as is seen with Leishmania donovani infections.     

B cell sensitivity to IgE-suppressive activity of IFN-gamma is polymorphic and controlled by a non-H-2-linked gene.

It has been suggested that at least two distinct genetic factors are involved in developing atopic diseases. One is the major histocompatibility complex which controls antigen-specific polymorphism of IgE antibody responses and the other is an unidentified factor(s) which controls isotype selection, i.e., class switching to IgE. It is conceivable that both expression of and sensitivity to lymphokines that play central roles in controlling IgE biosynthesis may be involved in the latter polymorphism. To explore this possibility, we have examined the sensitivities of several mouse strains to interleukin (IL)-4 and interferon-gamma (IFN-gamma). The results show that (1) the sensitivity to IgE-suppressive activity of IFN-gamma, but not to the IgE-enhancing activity of IL-4, is polymorphic (e.g., C57BL/6 is 8- to 16-fold more sensitive than BALB/c to IFN-gamma); (2) F1 of these two strains (CByB6F1) are BALB/c type and H-2 congenic mice of d haplotype with B6 background are C57BL/6 type, suggesting that low sensitivity is a non-H-2-linked dominant trait; (3) the polymorphism is determined at B cell levels; and (4) sensitivity to IFN-gamma is not associated with mRNA expression of IFN-gamma receptors (R) by B cells. These data collectively indicate that BALB/c mice have a non-H-2-linked gene which decreases B cell sensitivity to IFN-gamma, but the gene effect is not associated with the expression of IFN-gamma R mRNA on B cells. The possible biological significance of the non-H-2-linked gene is discussed.     

Variations in genetic control of susceptibility to Theiler's murine encephalomyelitis virus (TMEV)-induced demyelinating disease. I. Differences between susceptible SJL/J and resistant BALB/c strains map near the T cell beta-chain constant gene on chromosome 6

In some susceptible mouse strains, intracerebral (IC) inoculation of Theiler's murine encephalomyelitis virus (TMEV) results in a persistent infection leading to chronic demyelinating disease. Previous genetic analyses between susceptible SJL/J and resistant C57BL/6 mice indicated a role for multiple unlinked genes in the development of clinical and histopathological disease, including a major influence of the D region of the H-2 complex. In this study, genetic analysis of a different strain combination (susceptible SJL/J and resistant BALB/c) also demonstrates the involvement of multiple genes, but the H-2 genotype (H-2s and H-2d, respectively) does not appear to contribute significantly to susceptibility differences. In both segregation studies and recombinant-inbred (R-I) analysis, clinical and histopathological disease occurs in both H-2s homozygotes and H-2d homozygotes (as well as H-2s/H-2d heterozygotes), with the actual frequency related to the proportion of non-H-2 genome from the susceptible strain. There appear to be at least two non-H-2 genes involved in differential susceptibility of SJL/J and BALB/c to TMEV-induced disease. Analysis of R-I strains generated from BALB/c and SJL/J progenitors indicates linkage of at least one of these non-H-2 genes to those encoding the constant portion of the beta-chain of the T cell receptor on chromosome 6. Many genes may actually be involved, but each strain comparison defines a different subset of these loci--only those at which the two strains in question carry "functionally" different alleles. Thus, different strain comparisons may accent the roles of different genes in resistance to the same infectious organism or disease process. In addition to the genes identified thus far, there may be yet other genes contributing to development of TMEV-induced disease, but their recognition may require analysis of still other strain combinations.     

Dual role for nitric oxide in paracoccidioidomycosis: essential for resistance, but overproduction associated with susceptibility

Using a murine model of susceptibility and resistance to paracoccidioidomycosis, we have previously demonstrated that immunosuppression occurs in susceptible (B10.A), but not in resistant (A/Sn), mouse strains. Accumulating evidence shows that NO is involved in the induction of T cell immunosuppression during infection as well as in the killing of Paracoccidioides brasiliensis. In the present work, we focused on NO and other macrophage products that could be associated with resistance or susceptibility to paracoccidioidomycosis. A striking difference was related to NO and TNF production. Macrophages from B10.A mice produced high and persistent NO levels, while in A/Sn animals, TNF production predominated. In in vitro cultures, P. brasiliensis-infected macrophages from A/Sn mice also produced large amounts of TNF, while B10.A macrophages only produced NO. TNF production by B10.A macrophages appeared to be suppressed by NO, because the addition of aminoguanidine sulfate, an inducible NO synthase (NOS2) inhibitor, resulted in TNF production. These results suggested that enhanced TNF or NO production is associated with resistance and susceptibility, respectively. However, regardless of the mouse strain, NOS2-deficient or aminoguanidine sulfate-treated mice presented extensive tissue lesions with increased fungal load in lungs and liver compared with their controls. We conclude that NOS2-derived NO is essential for resistance to paracoccidioidomycosis, but overproduction is associated with susceptibility.     

The inheritance of thiabendazole resistance in Haemonchus contortus.

Haemonchus contortus worm populations isolated from naturally infected sheep at the Pastoral Research Laboratory, Armidale, N.S.W., were found to contain approximately 20% of worms resistant to a 50 mg/kg dose of thiabendazole. Following 3 generations of selection with 50 mg/kg thiabendazole the number of worms removed by the anthelmintic was too small to detect differences between treated and control groups. After more than 15 generations of selection, matings between males from the selected strain and non-resistant females produced resistant males and females in equal numbers. Thus, thiabendazole resistance does not appear to be sex-linked. A dose--response assay on the F2 adults indicated that worms from female resistant x male non-resistant crosses were more resistant than F2 adults of the reciprocal cross. An in vitro technique that identified thiabendazole-resistant eggs by their ability to hatch in a solution containing thiabendazole and 0.1% NaCl solution was also used to study the inheritance of resistance. F1 eggs had similar LC50's to the resistant parents. F2 and back-cross eggs from an original mating of thiabendazole-resistant females x non-resistant males had a higher LC50 than F2 and back-cross eggs from the reciprocal mating, indicating a degree of matroclinous inheritance of resistance. However, the resistant parents had tolerances to thiabendazole exceeding those of F2. F3 eggs had a resistance distribution that ranged from that of the resistant to the non-resistant parent. No significant deviation from linearity was observed in any of the dose--response lines. These results indicate that thiabendazole resistance in H. contortus worms is inherited as an autosomal and semi-dominant trait.     

Fine physical mapping of the rice stripe resistance gene locus, Stvb-i

The Stvb-i gene confers stripe disease resistance to rice. For positional cloning, we constructed a physical map spanning 1.8-cM distance between flanking markers, consisting of 18 bacterial artificial chromosome (BAC) clones, around the Stvb-i locus on rice chromosome 11. The 18 clones were isolated by screening a BAC library derived from a japonica cultivar, Shimokita, with three Stvb-i-linked RFLP markers and DraI-digested DNAs of a yeast artificial chromosome (YAC) clone. The results of Southern hybridization and restriction enzyme analyses indicated that these BAC clones are contiguous and cover about a 700-kb region containing the Stvb-i allele. Utilizing end and internal fragments of the BAC insert DNAs, 33 molecular markers were generated within a small chromosomal region including the Stvb-i locus. Genotyping analysis with these markers for a resistant cultivar and four nearby recombinants selected from 120 F₂ individuals indicated that Stvb-i is contained within an approximately 286-kb region covered with two overlapping BAC clones. Received: 25 August 1999 / Accepted: 16 November 1999     

Genetic control of tolerance induction to human gamma-globulin in mice.

Susceptibility to tolerance induction with monomeric human gamma-globulin (HGG) was tested in different inbred strains of mice. The results indicated a differential tolerance susceptibility among the strains and that the basis for the variation is genetic in nature. By using a protocol that permits genetic analysis, F1, F2, and backcross generations of the parental strains SJL/J and C3H/Bi were examined. A multigenic control model by H-2-linked and non-H-2-linked genes showing Mendelian autosomal inheritance is proposed.     

Hybrid resistance to BALB/c plasmacytomas. II. Radiation sensitivity and silica insensitivity of resistance to MPC-11.

Resistance to the BALB/c plasmacytoma MPC-11 by F1 hybrids between BALB/c and four C57BL/10 congenic resistant strains was abrogated or reduced by 450 rads total body irradiation but was unaffected by intravenous injection of 3 to 4 mg of silica. The results are consistent with the idea that hybrid resistance to MPC-11 depends on an active immune response and is different from Hh-1 controlled hybrid resistance.     

Graft-versus-host response,measured by splenomegaly assay,by populations of allosensitized mouse lymphocytes

The graft-vs-host (G-v-H) reactivity of sensitized or nonsensitized mouse lymphoid cell populations was measured using a splenomegaly assay. Sensitized populations were obtained either from the local lymph nodes of alloimmunized animals or from the spleens of heavily irradiated mice previously infused iv with allogeneic lymphocytes (educated cells). Immunization of animals resulted in increased G-v-H responses of the cells in their local lymph nodes. This effect was more pronounced when the immunizing cells differed only at non-H-2 transplantation antigens than when H-2-disparate strain combinations were tested. There was no evidence of a changed doseresponse profile of lymphocytes obtained from immunized mice. The G-v-H reactivity of educated cell populations was complex. The slopes of the dose-response lines obtained for lymph node cells or thymic cells educated in an H-2-disparate strain were generally lower than those obtained for nonsensitized cells. This difference was particularly evident when testing educated thymocytes. By studying the G-v-H indices obtained in A/Sn × C57B1 hybrids after inoculation of nonsensitized C57B1 lymph node cells or specifically educated C57BL lymph node cells, it was observed that the latter cells were approximately 30 times more reactive when small cell inocula were compared. On the contrary, education of lymphocytes in H-2-compatible allogeneic hosts did not result in any increment of their G-v-H reactivity. The results indicate that different methods of sensitizing lymphocyte populations against alloantigens may lead to activation of different subclasses of T-cells which differ in their mode of antigen reactivity.     

Localization on a physical map of the NKC-linked Cmv1 locus between Ly49b and the Prp gene cluster on mouse chromosome 6.

The Cmv1 locus controls NK cell-mediated resistance to infection with murine CMV. Our recent genetic analysis of backcross mice demonstrated that the NK gene complex (NKC)-linked Cmv1 locus should reside between the Ly49 and Prp gene clusters on distal mouse chromosome 6. We have aligned yeast artificial chromosome (YAC) inserts in a contig spanning the interval between the Ly49 and Prp gene clusters. This YAC contig includes 13 overlapping YAC inserts that span more than 2 megabases (Mb) in C57BL/6 (B6) mice. Since we have identified genomic clones that span the Ly49-Prp gene region, we hypothesize that at least one should contain the Cmv1 locus. To narrow the Cmv1 critical region, we developed novel NKC genetic markers and used these to genotype informative backcross and intra-NKC recombinant congenic mouse DNA samples. These data suggest that Cmv1 resides on a single YAC insert within an interval that corresponds to a physical distance of approximately 390 kb. This high resolution, integrated physical and genetic NKC map will facilitate identification of Cmv1 and other NKC-linked loci that regulate NK cell-mediated immunity.     

Construction of a potato YAC library and identification of clones linked to the disease resistance loci R1 and Gro1

 A yeast artificial chromosome (YAC) library was constructed from high-molecular-weight DNA of potato (Solanum tuberosum). Potato DNA fragments obtained after complete digestion with four different rare-cutter restriction enzymes were cloned using the pYAC-RC vector. The library consists of 21 408 YAC clones with an average insertion size of 140 kb. The frequency of YAC clones having insertions of chloroplast or mitochondrial DNA was estimated to be 0.5% and 0.3%, respectively. The YAC library was screened by PCR with 11 DNA markers detecting single genes or small gene families in the potato genome. YACs for 8 of the 11 markers were detected in the library. Using 2 markers that are linked to the resistance genes R1 and Gro1 of potato, we isolated two individual YAC clones. One of these YAC clones was found to harbour one member of a small family of candidate genes for the nematode resistance gene Gro1. Received : 5 May 1997 / Accepted : 20 May 1997     

Genetics of resistance to the African trypanosomes. VI. Heredity of resistance and variable surface glycoprotein-specific immune responses

The question of genetic linkage of parasite-specific immune responses to resistance to infection in experimental African trypanosomiasis was addressed. For this purpose, major histocompatibility complex-compatible resistant and susceptible inbred mouse strains and their F1 hybrid, F2 hybrid, and backcross offspring were infected with Trypanosoma brucei rhodesiense LouTat 1. Immunologic control of the first peak of parasitemia and survival times were the parameters measured. As we have reported previously (R. F. Levine and J. M. Mansfield, J. Immunol. 133:1564, 1984), B10.BR/SgSnJ mice are relatively resistant and controlled the growth of the infecting variant antigenic type (VAT) by mounting an antibody response to exposed epitopes of the variable surface glycoprotein (VSG). Fluctuating parasitemias resulting from sequential growth of different variable antigenic types occurred subsequently, and these mice died with a median survival time of 48 days. C3HeB/FeJ mice, relatively susceptible, did not control the infecting VAT and did not exhibit VSG-specific antibodies. These mice died with a median survival time of 22 days. The (B10.BR X C3H)F1 hybrids derived from crosses between resistant and susceptible mice all exhibited VSG-specific antibody responses and controlled the infecting VAT population. However, the median survival time of the F1 hybrids (24 days) was not significantly different from the survival time of the susceptible C3H parent. These findings demonstrate for the first time that antibody-mediated control of parasitemia is inherited as a dominant trait; that overall resistance, as measured by survival time, is inherited as a recessive trait (e.g., susceptibility is dominant); and that the two events segregate independently of one another. Further analyses of the inheritance of immunity and resistance (survival time) were made in which the F2 hybrid and backcross studies revealed that there are multiple genes controlling the VSG-specific antibody response as well as determining susceptibility. An extension of the present studies to a similar but non-major histocompatibility complex-mouse model system of resistance and susceptibility (C57BL/6J and C3H/HeJ mice, F1 hybrids, and 11 recombinant inbred B X H strains derived from them) was made in order to link the strain distribution patterns of known genetic markers with control of VSG-specific antibody responses or with control of susceptibility. Results of this study showed that resistance varied independently of the ability to control parasitemia with VSG-specific B cell responses.(ABSTRACT TRUNCATED AT 400 WORDS)