Specificity of IgA cold agglutinins: anti‐Pr₁

Abstract

Monoclonal cold agglutinins have usually been found t o be IgM(K) and t o be directed against the I/i antigens.'Three IgA(K) cold agglutinins were tested for antibody specificity. Based on the following criteria, they were shown t o be directed against the Pr, antigen of the Pr, /Prz/Pra antigen system. The antigens reacting with the IgA(K) cold agglutinins were inactivated by protease and treatment of human red cells with neuraminidase and were demonstrable on human erythrocyte glycoproteins. The terminal sugar of the determinant group of these antigens is N-acetylneuraminic acid (NANA), which is not involved in I/i, but also in Pr2 antigenicity. The antigen activity of these antigens and the Pr2 and I antigen activities were distributed t o different glycopeptide fractions obtained from red cell glycoproteins by ficin cleavage and Sephadex G-50 separation. Periodate oxidation of red cell glycoproteins, which causes a shortening of the polyhydroxy side chain at C-6 of C-9 NANA to a C-7 and/or C-8 NANA derivative, resulted in inactivation of these antigens, while the I antigen remained unchanged and the Pr, antigen was increased 16-64-fold. Dog red cells gave no or diminished reactions with the three IgA(K) cold agglutinins, in contrast to increased reaction with antiPrz. Based on the different reactions of the IgA(K) cold agglutinins with dog red cells, a Pr, heterogeneity Prlh/Prld was demonstrated.In spite of the determination of the Prlh/Prld/Prz and the MN antigens by NANA, both antigen systems were shown t o be unrelated. Blocking of free c-lysine amino groups by acetylation or blocking of the NANA carboxyl groups by amidation of red cell glycoproteins resulted in MN inactivation, while the antigens reacting with the IgA(K) cold agglutinins (like Pr2) remained unaffected.The anti-Prl specificity of IgA cold agglutinins and the predominance of anti-I/-i specificity of IgM cold agglutinins was discussed with respect t o interrelations between immunoglobulin classes and antibody specificities of cold agglutinins.As has been shown by Roelcke [26], the antigens Pr, and Pr, are also inactivated by neuraminidase (RDE), in contrast t o the Pr, antigen. Pr1/Pr2/Pra are present on all adult and newborn erythrocytes in equal amounts, which is not true for the l/i antigens [23].Two of the three Pr antibodies described by Roelcke [ 17, 261 were not of the IgM class. Anti-Pr, was a monoclonal IgA(K) cold agglutinin [ 141, anti-Prz was a monoclonal K-type macroglobulin. Anti-Pr, was a transiently occurring 1gG cold agglutinin (found in a child with Mycoplasma pneumoniae infection) [ 171.

Anti-Pr (3): Serological and Immunochemical Identification of a New Anti-Pr Subspecificity

“…The most significant data obtained with anti-Pr CA were (1) the demonstra tion of IgA(x) CA to be anti-Prj [19]; (2) the detection of a new chain variable region subgroup V*iv [29], and (3) the demonstration of cross-idiotypic specificities among IgA and IgM anti-Pr CA distinct from cross-idiotypic specificities within anti-I/-i CA [7]. Because it is known that (1) Prt determinants are complex [19,24]; (2) there are single ex changes within the amino acid sequences of the V*iv subgroup [11,29], and (3) the cross-idiotypic determinants of anti-Pr CA are complex [7], the identification of single Pr determinants, e.g. Pr3, may be useful to assign certain antibody structure characterisitics to single Pr determi nants.…”

“…The anti-I No. was used, which has been shown to be a 'poly valent' anti-I sample in Ouchterlony double diffusion studies [19,22], Anti-MI-N sera were obtained by rabbit immunization and appropriate ab sorption procedures.…”

The Electrokinetic Behavior of Red Blood Cells from a Patient with Tn Syndrome by Doppler Electrophoretic Light Scattering Analysis.

“…The procedure of papain treatment was performed following the method of Roelcke (Roelcke 1973). Water-soluble papain (Wako, Osaka) was used at a concentration of 209 PU/ml in 1/15 M PBS, pH 7.3.…”

Idiotypic and Structural Analysis of Monoclonal Human Immunoglobulins with Anti-Streptolysin·Activity

“…constant parts of immunoglobu lins) indicates that ASO activity may be associated with IgG, IgA, and even IgD; however, IgG, especial ly of the subclass G] and the K-type of the L chain, predominates. Since IgGik is the overwhelming frac tion in normal human immunoglobulins, a much greater number of myeloma proteins with ASO activi ty would have to be analyzed either to prove or to re fute an association between ASO activity and IgG]K. A restriction to a single immunoglobulin subclass and type has been shown for human anti-carbohydrate antibodies [22,35] and for cold agglutinins [24,27], An association between structure and specificity, however, is much more to be expected for the variable part of immunoglobulins than for the constant part, since the combining site resides in this section of the molecule. The L chain N-terminal amino acid se quences of the proteins O.I., L.F. and A.S. indicate that all three L chains fall into the same variable re gion subgroup, VkIII, while the H chains of both pro teins, O.I.…”