Response of vaccinated and nonvaccinated syngeneic C57B1-6 mice to infection with Mycobacterium tuberculosis

The relevance to protection of three forms of delayed skin-test response evoked by m. leprae and other mycobacteria in mice. Correlation with the classical work in the guinea-pig

The controversy surrounding the protective role of 'delayed hypersensitivity' in tuberculous guinea-pigs has never been resolved. This controversy has arisen because the term 'delayed hypersensitivity' is used indiscriminately to describe both a type of necrotic skin-test reactivity which does not appear until 4-6 weeks after infection, and also non-necrotic reactions which can be elicited within a few days. Responses closely analogous to both have been characterized in mice immunized with mycobacteria. Simple criteria are described which allow these responses to be distinguished from one another, and from the Jones-Mote phenomenon. The relevance of each type to protection, susceptibility and immunopathology in leprosy, tuberculosis, leishmaniasis and listeriosis is discussed.

The AXB and BXA set of recombinant inbred mouse strains

The recombinant inbred (RI) set of strains, AXB and BXA, derived from C57BL/6J and A/J, originally constructed and maintained at the University of California/San Diego, have been imported into The Jackson Laboratory and are now in the 29th to 59th generation of brother-sister matings. Genetic quality control testing with 45 proviral and 11 biochemical markers previously typed in this RI set indicated that five strains had been genetically contaminated sometime in the past, so these strains have been discarded. The correct and complete strain distribution patterns for 56 genetic markers are reported for the remaining RI strain set, which consists of 31 living strains and 8 extinct strains for which DNA is available. Two additional strains, AXB 12 and BXA 17, are living and may be added to the set pending further tests of genetic purity. The progenitors of this RI set differ in susceptibility to 27 infectious diseases as well as atherosclerosis, obesity, diabetes, cancer, cleft palate, and hydrocephalus. Thus, the AXB and BXA set of RI strains will be useful in the genetic analysis of several complex diseases.

Racial differences in susceptibility to tuberculosis: risk of disease after infection

It is generally believed that certain racial groups are highly susceptible to tuberculosis disease while others have developed a "natural resistance." Epidemiological studies reporting differences in case rates among different racial groups, provide inconclusive evidence. Many factors influence the development of active tuberculosis including sex, age, body weight, and virulence of the infecting organism. These, as well as other factors, may be more important determinants which, up to now, have been confused with race.

The effect of two distinct forms of cell-mediated response to mycobacteria on the protective efficacy of BCG

The previous paper presents evidence that prior exposure to some environmental mycobacteria enhances the protective efficacy of BCG, whereas exposure to other species opposes it, and suggests that these different species act by evoking one of two types of cell-mediated response of different protective efficacy. This paper reviews past evidence for the existence of these two types of response, and suggests that both can be demonstrated in mice. The type of response evoked in mice by environmental species correlates with their effect on the efficacy of BCG in man, and with the type of proliferative response evoked in human peripheral blood lymphocytes by their soluble antigens in vitro. Preimmunisation of mice to give one type of response can block subsequent induction of the other. We therefore present a model, based on this principle, for the interaction of contact with environmental mycobacteria with subsequent BCG vaccination.

The specificity of suppressor T cells induced by chronic Mycobacterium avium infection in mice

Normal mice infected intravenously with 10(6) or 10(8) viable M. avium develop persistent infections of the lungs, liver and spleen. The liver and spleen counts remained relatively constant whereas those for the lung slowly increased until eventually some of the animals began to die as a result of the infection. None of the heavily infected mice developed delayed hypersensitivity (DTH) to the M. avium cytoplasmic protein antigen (CPA). Spleen cells harvested at increasing time periods after the M. avium infection were tested for their blastogenic responsiveness to PHA and M. avium CPA. The presence of suppressor T cells within the heavily infected spleens was demonstrated by means of cell-mixing experiments before and after treatment of the anergic spleen cells with anti-Thy-1.2 antiserum and complement. The specificity of the suppressor T cells was measured in terms of their ability to depress responsiveness to sheep erythrocytes and an allograft challenge. Initially, the suppressor T cell population affected all of the T cell-mediated responses but as the infection progressed, so the non-specific host responses tended to return gradually towards normal, whereas the specific M. avium CPA-mediated suppression persisted largely unchanged.

Local immune response to Mycobacterium lepraemurium in C3H and C57Bl/6 mice

Subcutaneous footpad inoculation of living M. lepraemurium (L.MLM) induced, in high responder C57Bl/6 mice, a local granulomatous reaction associated with the production of effector cells which stopped the multiplication of bacilli in the draining popliteal node with the concurrent development of 24--48 hr delayed type hypersensitivity (DTH). The thymus-dependent local reaction did not occur after the injection of heat-killed M. lepraemurium (HK.MLM) or after the inoculation of L.MLM in nude mice. However, HK.MLM injection interfered with the onset of the local reaction and enhanced acid-fast bacteria (AFB) counts in the draining node. In low responder C3H mice, L.MLM produced a local and delayed footpad swelling but no restriction of bacilli multiplication in the draining lymph node was observed. This unresponsiveness was not due to an overloading of the inoculum dose since doses ranging from 3 x 10(4) to 3 x 10(7) MLM did not produce any granulomatous local reaction as in C57Bl/6 mice. The injection of dead bacilli in the contralateral footpad of subcutaneously (s.c.) infected C3H mice revealed Arthus-like and 18--24 hr delayed reactions. When 10(6) L.MLM per mouse were injected intravenously (i.v.), systemic infection, measured in the spleen, was found to be less restricted in C57Bl/6 than in C3H mice. Moreover, in C57Bl/6 mice low doses of L.MLM injected i.v. delayed the local reaction at first, then enhanced footpad swelling and AFB counts in the draining nodes, indicating some acquired defect of peripheral immunity. When a high dose of L.MLM (2 x 10(8)/mouse) was injected i.v., C57Bl/6 mice died sooner than C3H mice, indicating certain discrepancies between local resistance and systemic susceptibility.

Immunological behavior after mycobacterial infection in selected lines of mice with high or low antibody responses

Resistance and susceptibility to mycobacterial infection in the Biozzi high and low lines of mice which were genetically selected for their responses to heterologous erythrocytes have been found to be related to the innate ability of nonimmune macrophages to kill or inhibit the growth of the organisms during the first two weeks after infection and to their ability to mount specific and nonspecific immune responses. High antibody-producer mice were more capable of expressing cell-mediated immune parameters than low antibody-producer mice. A direct relationship was observed between the ability of bacteria (BCG vaccine) to multiply inside the reticuloendothelial system and the development of cell-mediated immunity, as measured by the delayed local reaction at the injection site, the lymphoproliferative response in the draining nodes, the tuberculin delayed-type hypersensitivity, the acquired resistance, and the adjuvant effect after BCG inoculation. In high line mice, apart from the inability of their macrophages to inhibit the early growth of bacteria, their lymphocytes in spleen and thymus were more capable of being stimulated in vitro by varying concentrations of living BCG. The data presented in this report are compatible with the hypothesis that a group of genes segregated in each line during the selective breeding controls the innate microbicidal activity.

Induction of cell-mediated immunity to Mycobacterium lepraemurium in susceptible mice

A mouse strain (CB6) that is highly susceptible to Mycobacterium lepraemurium was infected with 10(8) bacilli into the hind footpad. These mice developed cell-mediated immunity to M. lepraemurium, as expressed by the development of a granulomatous lesion at the site of inoculation in normal but not in T-lymphocyte-depleted mice, a proliferative response in the paracortical zone of the draining lymph node, delayed-type hypersensitivity to a sonic extract of M. lepraemurium, and immunopotentiation of the delayed hypersensitivity response to sheep erythrocytes. Resistance to a second challenge infection with M. lepraemurium was not demonstrated.

Relationship between tuberculin hypersensitivity and cellular immunity to infection in mice vaccinated with viable attenuated Mycobacterial cells or with Mycobacterial ribonucleic acid preparations

The migration inhibition technique has been used to study delayed hypersensitivity in vitro by using peritoneal exudate cells and splenic lymphocytes from mice vaccinated with viable cells of the attenuated H37Ra strain of Mycobacterium tuberculosis and from mice vaccinated with ribonucleic acid (myc RNA) preparations obtained from viable mycobacterial cells of the same strain. Inhibition of macrophage migration was noted when purified protein derivative (PPD) or viable H37Ra cells were added to peritoneal exudate cells obtained from mice immunized with viable H37Ra cells and not from mice immunized with myc RNA. Splenic lymphocyte cultures were exposed to the same antigens in vitro. Filtered supernatant fluids from these lymphocyte cultures, when added to peritoneal exudate cells obtained from nonimmunized mice, inhibited migration only when they were obtained from lymphocytes which came from mice immunized with viable H37Ra cells. Injection of PPD intravenously into vaccinated mice resulted in inhibitory supernatant fluids from splenic lymphocyte cultures only when the lymphocytes came from mice immunized with viable H37Ra cells. However, intravenous injection of either viable H37Ra cells or of myc RNA preparations into mice vaccinated with myc RNA occasionally produced inhibitory supernatant fluids when lymphocytes were obtained from these mice. On the other hand, mice vaccinated with myc RNA or viable H37Ra cell preparations were consistently and equally protected against intravenous challenge with the virulent H37Rv strain. Thus, although some evidence was obtained for a delayed type hypersensitivity in mice vaccinated with H37Ra cells or with myc RNA to ribosomal proteins or other proteins associated with the RNA preparation, no evidence of tuberculin hypersensitivity could be detected in any mice vaccinated with the myc RNA. These results argue against a role for tuberculin hypersensitivity in immunity to tuberculous infection.