Functional and Serological Examination of the Central Portion of the I Region of the H-2 Gene Complex.

The I region of five intra-I region recombinant mouse strains, B10.ASR7(H-2('as3)), B10.BASR1 (H-2('as4)), B10.S(8R) (H-2('as1)), B10.BAR4(H-2('h6)), and A.TFR5(H-2('ap5)) was examined serologically and functionally. When the five strains were examined serologically, they were all found to possess crossover positions between the I-A and the I-E subregions. The I-B and the I-J subregions could not be examined serologically since no gene products have ever been identified for these two subregions; however, functional assays were used to examine the I-B and the I-J subregions. The immune response to the myeloma protein MOPC 173 was used to assign I-B alleles, while the haplotype restriction of the macrophage-T cell interaction for the primary in vitro antibody response to burro red blood cells was used to assign I-J alleles. By assigning I-B and I-J alleles, the recombinatorial positions were determined for the five strains. B10.BASR1 and A.TFR5 were found to have crossover positions between the I-A and the I-B subregions, while B10.ASR7, B10.S(8R), and B10.BAR4 were determined to be recombinants between the I-B and the I-J subregions. The existence of the I-B subregion was confirmed by the crossover positions in these five strains. The crossover position in B10.BASR1 and A.TFR5 defined the centromeric boundary of the I-B subregion and the telomeric boundary was established by the recombinatorial event in B10.ASR7, B10.S(8R), and B10.BAR4. Using various combinations of the recombinant strains in mixed lymphocyte reactions, the I-B subregion was tested to ascertain if it coded for any lymphocyte activating determinants. No responses were detected in any of the different combinations, from which it was concluded that the I-B('k), I-B('b), and I-B('s) alleles do not code for any lymphocyte activating determinants. This examination of the intra-I region recombinant strains has added to the knowledge of the genetic composition of the H-2 gene complex and these strains will serve as excellent probes with which to further examine the central portion of the I region.Ph.D.ImmunologyUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/158392/1/8125058.pd