Failure to Demonstrate Dosage of U Antigen

Abstract

Tests in which 11 examples of anti-U were used in titration studies against the red blood cells of 9 obligate Uu heterozygotes, from 4 unrelated families, and random Negro and Caucasian donors (many of whom were of the presumptive UU genotype) have failed to demonstrate any dosage of the U antigen.

The MiIII phenotype among Chinese donors in Hong Kong: immunochemical and serological studies

“…No significant differences in strength were observed between control Ss, ss or obligate sS" cells or cells from any family member. Failure to demonstrate dosage of U antigen on obligate heterozygous S" cells has been previously reported (Issitt et al, 1976). All the members of families 107, 129, and 174 were Dantu negative.…”

Inherited Lack of Ss Antigens with Weak Expression of U in a Caucasian Family

“…U13-AA) gave scores of 18-34 whereas random normal panel cells scored 44-64. Other workers have not been able to differentiate between homozygotes and heterozygotes using anti-U [4,5]. Gold stein [5] describes dosage tests on appro priate members of 15 Negro families with S-s-probands, but no clear effect could be shown in any of the members.…”

“…Gold stein [5] describes dosage tests on appro priate members of 15 Negro families with S-s-probands, but no clear effect could be shown in any of the members. Issitt et al [4] describe unsuccessful attempts with 11 different anti-U sera in titration studies against obligate Uu heterozygotes to demon strate dosage for the U antigen. The same workers [4] postulate, as a result of their findings, that when one u gene replaces one U gene at the Uu sub-locus, a double dose of U antigen may still be made and that this is dependent on the amount of precursor material available, while in the genetic situ ation UMk, only half the normal amount of precursor material is available.…”

“…Issitt et al [4] describe unsuccessful attempts with 11 different anti-U sera in titration studies against obligate Uu heterozygotes to demon strate dosage for the U antigen. The same workers [4] postulate, as a result of their findings, that when one u gene replaces one U gene at the Uu sub-locus, a double dose of U antigen may still be made and that this is dependent on the amount of precursor material available, while in the genetic situ ation UMk, only half the normal amount of precursor material is available. It can also be argued that the UMk and Uu ge netic situations both involve the presence of a single U gene, so that red cell U antigen levels in the two would be expected to be similar.…”