TABLE 1.

MAbs used in this study

MAb	Specificity	Isotypea	Source (reference)
4D2	H type I	IgM	R. Negrinib (2)
54.1F6A	Lex	IgM	G. J. van Damc (20)
Hp151	Ley	IgG	R. Negrini (2)
NAM61-1A2	i-Antigen	IgM	D. Blanchardd (10)
218/2B3	Lea, Leb	IgM	Isosepe

^aIg, immunoglobulin. 

^bLaboratory Unit, City Hospital, Brescia, Italy. 

^cDepartment of Parasitology, University of Leiden, Leiden, The Netherlands. 

^dRegional Blood Transfusion Service, Nantes, France. 

^eTullinge, Sweden; the supplier documents this MAb as specific for Le^a, while our own data (Table 2) indicate an additional specificity for Le^b and LNT.