CROSSING OVER BETWEEN GENES IN THE IMMUNOGLOBULIN HEAVY CHAIN LINKAGE GROUP OF THE MOUSE

Immunoglobulin heavy chain genes were found in wild mice (Mus musculus) that could best be explained as recombinants of immunoglobulin genotypes. In wild mice from Kitty Hawk, N. C., two new heavy chain linkage groups, G3,5,7,8H9,11FfA- and G3,5,8H9,11FfA-, were found, each of which genetically controls both the 3 and 5 distinct immunoglobulin determinants. In inbred strains the 3 and 5 determinants are found independently. The new heavy chain allotype G3,5,7,8H9,11FfA- probably arose from a homologous (intragenic) cross-over between G3,8H9,11FfA- and G5,7,8H9,11FfA14 heavy chain linkage groups. It was suggested that genes controlling G3,8G5,7,8, G3,5,8, and G3,5,7,8 are alleles. Another homozygous wild mouse (Kyushu, Japan) showed a new heavy chain allotype, 2G1,6,7,8H9,16FsA15. The 2 and G1,6,7,8 determinants are also separated in inbred strains. The 2 determinant in inbred mice is not on the γF, γH, or γA heavy chain and is probably on a γG or γG-like immunoglobulin heavy chain. Papain digestion of serum from the Kyushu mouse showed two electrophoretically different Fc fragments, one carrying the G1,6,7,8 and the other the 2 determinant. The new heavy chain allotype, 2G1,6,7,8H9,16FsA15, of the Kyushu wild mouse probably arose from a nonhomologous (unequal) cross over between 2G-H9,16FsA15 and G1,6,7,8H9,11FfA12,13,14 heavy chain linkage groups. The linkage group of the Kyushu wild mouse has at least five heavy chain genes, while that of the inbred mice has four

COMMON INDIVIDUAL ANTIGENIC DETERMINANTS IN FIVE OF EIGHT BALB/c IGA MYELOMA PROTEINS THAT BIND PHOSPHORYL CHOLINE

Eight IgA myeloma proteins derived from independently induced plasma-cytomas in genetically similar inbred BALB/c mice are functionally related by their binding of phosphoryl choline-containing antigens (Pneumococcus C polysaccharide or Lactobacillus antigen). Each protein resembles a single species of immunoglobulin in antibody. The proteins are characterized by highly sensitive myeloma-specific antisera prepared by immunizing mice of other inbred strains with the BALB/c myeloma proteins. Individual or myeloma-specific determinants located on Fab fragments were found on three of the proteins that were unique for that protein and did not react with any other IgA protein among over 70 tested. Remarkably, five of the proteins shared two common myeloma-specific determinants which were specific for this group of five proteins. These results suggest that the five functionally and genetically related proteins sharing the same myeloma-specific determinants might also be structurally similar

ONTOGENY OF B LYMPHOCYTES : III. H-2 LINKAGE OF A GENE CONTROLLING THE RATE OF APPEARANCE OF COMPLEMENT RECEPTOR LYMPHOCYTES

The frequency of lymphocytes bearing complement receptors in the spleens of 2-wk old mice appears to be controlled by two independent genes. The presence of a "high" allele at either locus leads to intermediate or high frequency of CRL at 2 wk of age. One of the genes controlling complement receptor lymphocyte (CRL) frequency (CRL-1) is linked to the H-2 complex. Thus, in progeny of (AKR x DBA/2)F1 x DBA/2, all mice with a low frequency of CRL at 2 wk of age are homozygous for the H-2 type of the low CRL parent (DBA/2). Furthermore, in the B10 series of congenic mice, CRL frequency at 2 wk of age is similar to the frequency in the donor of the H-2 region. Thus, C57BL/10, B10.BR, and B10-D2 mice are all of the low CRL type while B10.A mice are intermediate in CRL frequency at 2 wk. C57BR and DBA/2, the donors of the H-2 complex of the B10.BR and B10.D2, respectively, are of low CRL type while the A/WySn, the donor of the H-2 complex in the B10.A, is an intermediate CRL strain. Similarly in the A/WySn series of congenic mice, A.CA, A.SW, and A.BY are all low CRL strains while the A/WySn is intermediate. Studies of CRL frequency in mice with recombinant H-2 chromosomes (B10.A(2R), (4R), and (5R); B6/TL+; and A/TL-) indicate that CRL-1 is to the right of the Ss-Slp genes and to the left of Tla

Plasma Electronics

Contains reports on eight research projects.National Science Foundation (Grant G-24073)United States Atomic Energy Commission (Contract AF(30-1)-3285)Lincoln Laboratory (Purchase Order DDL BB-107)United States Air Force (Contract AF19(628)-500)United States Atomic Energy Commission (Contract AT(30-1)-3221

Plasma Electronics

Contains reports on ten research projects.U. S. Air Force under Contract AF 19(628)-500U. S. Atomic Energy Commission under Contract AT(30-1)-3211U. S. Atomic Energy Commission under Contract AT(30-1)-3221National Science Foundation (Grant G-24073)Lincoln Laboratory, Purchase Order DDL BB-10