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The A 1 (B) phenomenon: a monoclonal anti‐B (BS‐85) demonstrates low levels of B determinants on A 1 red cells
Author(s) -
Voak D.,
Sonneborn H.,
Yates A.
Publication year - 1992
Publication title -
transfusion medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.471
H-Index - 59
eISSN - 1365-3148
pISSN - 0958-7578
DOI - 10.1111/j.1365-3148.1992.tb00145.x
Subject(s) - chemistry , monoclonal antibody , agglutination (biology) , antibody , biochemistry , protease , microbiology and biotechnology , transferase , enzyme , biology , immunology
SUMMARY. A monoclonal anti‐B (BS 85) that reacts strongly with red cells from weak B variants (B 3 , B int and B v ) has demonstrated the presence of a trace of B on A 1 red cells. The agglutination of group A 1 red cells by an anti‐B antibody is called the A 1 (B) phenomenon and is the converse of the B(A) phenomenon seen with certain monoclonal anti‐A antibodies. Fragile A 1 (B) agglutination is best seen by spin‐tube techniques and A 1 red cells negative in saline tests are agglutinated by albumin and protease enzyme‐enhanced tests, but no reactions are seen with A 2 red cells. The A 1 (B) reaction is specifically inhibited by B substance, and D‐galactose and the galactose‐containing sugars melibiose and lactose. Red cells from B variants showed differential inhibition patterns with various sugars. A 1 transferase levels were normal even in the strongest A 1 (B) reactive blood samples, although the plasma H transferase levels and H status of these red cells were elevated. This is in contrast to the B(A) phenomenon which is associated with elevated levels of B transferase. It is suggested that A 1 (B) overlapping specificity can occur because of a combination of higher H activity (and thus more H sites) together with normal levels of A transferase activity as they are 20% higher than normal levels of B transferase. The production of anti‐B reagents free of the A 1 (B) phenomenon with BS‐85 is achieved by suitable dilution using quality control tests with protease‐treated A 1 red cells. BS 85 anti‐B supernatant binds so strongly to B cells that it elutes only weakly by heat methods and therefore the B antigen cannot be demonstrated by the elution technique.