Sj, a New Antigen in the MN System, and Further Studies on Tm¹

Abstract

A serum containing antibody activity within the MN blood group system is described. Absorption studies showed that the serum detects two new antigenic determinants that have been named Tm and Sj. The results obtained when 1,400 bloods, 500 from Negroes and 900 from Caucasians, were tested for ten antigens in the MN system -M, MI, N, S, s, U, Hu, He, Tm and Sjare presented. Unlike most of the recently described new antigens in the MN system both Tm and Sj are of fairly high frequency in Caucasians and Negroes. Calculations of gene frequencies from these data are published in an accompanying paper [7].

Hemolytic Disease of the Newborn due to Anti-N

“…We sus pect that this variation may have been related to pH for it is well known [4,12] that some antibodies in the MN system react better at acid than at neutral or alkaline pH levels.…”

Failure to Demonstrate Dosage of U Antigen

“…Control red blood cells were collected at random from 18 Negroes and 5 Caucasians. Based on the highest reported incidence of the U-negative phenotype [1,5,6,18], it can be calculated that approximately 20% of Negroes are genetically Vu. Thus, in a series of 18 such bloods, the probability is that between 1 and 7 were from genetically Vu individuals with the most likely number being 3 or 4 (gene frequen cies and probabilities for the most likely number of Vu persons included, kindly calculated by Dr. F. H. Allen jr.).…”

An Rh Gene Complex which Results in a ‘New’ Antigen Detectable by a Specific Antibody, Anti-Rh 33

“…However the cells of H.H. failed to react with a battery of antisera to low frequency antigens, except anti-Sj [4] and some anti-Bg sera, probably those containing anti-Bga [11]. Neither nor Bg(a +) cells reacted with Coll, serum.…”