Parthenogenetically activated BCF1 and fertilized BALB/c embryos were aggregated to form chimaeras. The fate of the parthenogenetic component was followed in the conceptus during the second half of gestation. The results indicate an early strong selection against parthenogenetic cells in the extra-embryonal part, which is presumably complete by term, and a weaker selective process in the embryo...

The cytotoxic T-lymphocyte response against lymphocytic choriomeningitis virus (LCMV) in BALB/c mice is predominantly directed against a single, Ld-restricted epitope in the viral nucleoprotein (residues 118 to 126). To investigate whether any Kd/Dd-restricted responses were activated but did not expand during the primary response, we used a BALB/c mutant, BALB/c-H-2dm2, which does not express ...

Immune sera obtained from either BALB/c mice (susceptible) at 7 weeks, or C57BL/6 mice (resistant), at 7 weeks after infection with L. m. amazonensis, were effective in increasing internalization of homologous promastigotes into starch-induced peritoneal macrophages (from both mouse strains). Both the internalization enhancing effect and the levels of anti-leishmanial antibody (ELISA) were remo...

E10-5A3 is a dhfr-ts- Leishmania major double knockout auxotrophic shown previously to induce substantial protection against virulent L. major infection in both genetically susceptible and resistant mice. We investigated the capacity of dhfr-ts- to protect against heterologous infection by L. amazonensis. The degree of protection was evaluated by immunization of BALB/c or C57BL/6 mice with E10-...

While C-type RNA viruses are known to induce leukemias and lymphomas, oncogenic transformation of lymphoid cells by them in vitro has not been reported. In this study, splenocytes from female BALB/c mice were infected in vitro with Abelson virus, a C-type RNA virus that induces nonthymic lymphomas and plasmacytomas in mice. The cells were transplanted into recipients of different karyotype, eit...

Behavioural and psychological needs of laboratory animals generally cannot adequately be met in standard laboratory cages. Environmental enrichment, which provides a more structured environment can enhance the well-being of laboratory animals. They may perform more of their species-specific behaviour and may control their environment in a better way. An easily applicable form of enrichment for ...

The number of initiation points for DNA synthesis per unit length of DNA in rapidly growing cells is greater for simian virus 40-transformed than for nontransformed BALB/c 3T3 cells.

Accumulating evidence suggests that IL-9-mediated immunity plays a fundamental role in control of intestinal nematode infection. Here we report a different impact of Foxp3⁺ regulatory T cells (Treg) in nematode-induced evasion of IL-9-mediated immunity in BALB/c and C57BL/6 mice. Infection with Strongyloides ratti induced Treg expansion with similar kinetics and phenotype in both strains. Strik...

Both Leishmania major and L. braziliensis induce cutaneous leishmaniasis in BALB/c mice. Whereas BALB/c mice die of infection with L. major, they cure an infection with L. braziliensis. We report here that after curing an infection with L. braziliensis, BALB/c mice are resistant to challenge with L. major. When challenged with L. major, L. braziliensis pre-treated BALB/c mice mounted a delayed-...