Immune responses in newly developed short-lived SAM mice. IV. Chromosomal location of a gene controlling defective helper T-cell activity.
Short-lived SAMP-P/1 mice are low responders in in vitro antibody responses because of a selectively impaired helper T(Th)-cell activity. After crossing with high responders (B10.BR mice), about 12% of (B10.BR x SAM-P/1) (BRP)F2 mice showed low responsiveness, as did SAM-P/1 mice, against two T-dependent antigens, sheep and horse red blood cells (RBC), both of which were not cross-reactive to each other at helper T- and B-cell levels. The immune activities against the two antigens in individual BRPF2 mice showed a good correlation (r = 0.81), thereby suggesting that SAM-P/1 mice have an antigen non-specific Th cell dysfunction. Based on the incidence of the low responders in F2 generation and statistical analyses, the hypo-responsiveness was postulated to be controlled by two genes. To survey the location of these genes, linkage analyses were performed in the F2 mice using a large set of genetic markers. Low responders in the F2 generation showed a significantly higher incidence of SAM-P/1 genotype at the Gpi-1 as well as c locus on chromosome 7 (Chr.7). However, no linkage of low responsiveness to the Hbb locus was evident, an area present at a more distal site to the centromere on the same chromosome. These results suggest that one of the genes controlling the hypo-responsiveness of SAM-P/1 mice is linked to both Gpi-1 and c loci and that it locates at a more proximal site on Chr.7.
Hanada
K
K
Department of Senescence Biology, Kyoto University, Japan.
Katoh
H
H
Hosokawa
T
T
Hosono
M
M
Takeda
T
T
D000818:Animals; D000917:Antibody Formation / Q000235:genetics*; D001402:B-Lymphocytes / Q000276:immunology; D002874:Chromosome Mapping; D004912:Erythrocytes / Q000276:immunology; D008040:Genetic Linkage; D005819:Genetic Markers; D005838:Genotype; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains / Q000235:genetics*; D013154:Spleen / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D005819:Genetic Markers