Reactions of Murine Monoclonal Antibodies to Blood Group MN Antigens

Abstract

BALB/c mice were immunized by intraperitoneal injections with human blood group substances; 4 mice with M and 4 with N. Immune spleen cells were fused with murine myeloma cells X63-Ag-8.653. Two clones secreting monoclonal anti-M and seven secreting monoclonal anti-N were identified. All antibodies were of IgG(1) subclass and had κ light chains. Three clones have been maintained that produced antibodies useful for typing purposes: anti-M, A09 originating from a mouse injected with M, anti-N, AH7 originating from a mouse injected with N, and anti-N BO10 originated from a mouse injected with M substance. In typing 370 erythrocyte samples, monoclonal reagents gave identical results with commercial anti-M or anti-N typing sera of rabbit origin. Significantly, anti-N reagent AH7 obtained by immunization with N substance showed serological differences from anti-N reagent BO10 obtained by immunization with M substance in that AH 7 had apparently higher avidity to N specificity on glycophorin A of N erythrocytes than BO10, whereas BO10 showed higher avidity for ‘N’ specificity on glycophorin B of M and N erythrocytes than AH7. These two reagents showed also somewhat different patterns of reaction with enzymatically digested erythrocytes. This apparent serologic difference between N and ‘N’ specificities is at variance with current immunochemical data.

Construction of dimeric F(ab) useful in blood group serology

“…Because human anti‐M and anti‐N can be clinically significant, 7 it is important to have suitable reagents for antigen typing of donor RBCs. To this end, several groups produced and characterized multiple mouse hybridoma‐derived MoAbs recognizing M and N 8‐12 …”

A molecular approach for isolating high‐affinity Fab fragments that are useful in blood group serology

“…Because human antibodies to M and N can be of clinical significance, 6 it is important to have suitable reagents for typing human RBCs for these antigens. To this end, several groups produced and characterized mouse monoclonal antibodies (MoAbs) recognizing M or N 7–11 …”

Alteration of amino acid residues at the L‐chain N‐terminus and in complementarity‐determining region 3 increases affinity of a recombinant F(ab) for the human N blood group antigen

“…In addition, the Ser and Thr residues at positions 2, 3, and 4 are each modified by an O‐linked disialylated tetrasaccharide 21,22 . To date, many different M‐ and N‐specific mouse MoAb have been described, 23‐33 most of which recognize glycopeptide epitopes determined by both the amino acid polymorphisms and the attached O‐glycans 23,25 , 26,28‐30 , 34,35 …”