Laminin binds specifically to sulfated glycolipids

Previous studies of the agglutination of erythrocytes by the basement membrane glycoprotein laminin have suggested that laminin binds to gangliosides [Kennedy, D.W., Rohrbach, D.H., Martin, G.R., Momoi, T. & Yamada, K.M. (1983) J. Cell. Physiol. 114, 257-262]. Based on the following evidence, however, we find that laminin binds specifically to sulfatides, not gangliosides. Monogalactosyl sulfatides, purified from sheep erythrocytes with a yield of 4.3 mg/kg of packed cells, bound laminin with high affinity as did authentic bovine brain sulfatide (galactosylceramide-I3-sulfate). The binding activity of these lipids and of total erythrocyte lipids was stable to alkali and neuraminidase treatment but labile to dilute acid under conditions that destroy sulfatides but not gangliosides. Of various glycolipid and phospholipid standards tested, only sulfatides bound laminin with high affinity. Sulfatide binding and agglutinating activities of proteolytic fragments of laminin indicated that the globular end regions of the 200-kDa subunits are required for both activities. Thus, monogalactosylsulfatides, and possibly other more complex sulfated glycolipids, are probably involved in the agglutination of erythrocytes. These results also suggest a physiological function of sulfatides in cell adhesion. The agglutination of erythrocytes by fibronectin is also inhibited by gangliosides [Yamada, K.M., Kennedy, D.W., Grotendorst, G.R. & Momoi, T. (1981) J. Cell. Physiol. 109, 343-351]. Fibronectin, however, did not bind to sulfatides with high affinity but rather bound with low affinity to all anionic lipids tested, including phospholipids, gangliosides, and sulfatides.

Neutralization of Lewis blood group antibodies by synthetic immunoadsorbents

The neutralization of antibodies to the Lewis blood group systems is important in confirming the presence of these antibodies and in investigating complex alloantibody problems. An improved method for neutralizing Lewis antibodies is described. Insoluble immunoadsorbents containing synthetic Lewis antigens are used to physically remove the antibody from serum. Thirty-five sera containing Lewis antibodies were neutralized completely using this technic; 23 non-Lewis alloantibodies were not inhibited. In contrast with current methods, this technic does not dilute the patient serum and results in an affinity purified serum sample.

A technetium-99m red cell survival technique for in vivo compatibility testing

A technique for labeling red cells with Technetium-99m was developed using in vitro reduction by stannous pyrophosphate. The use of Technetium-99m and Chromium-51 enabled simultaneous determination of 60-minute autologous and heterologous red cell survival using small aliquots. In vivo pretransfusion red cell compatibility in a patient with a panagglutinin was identical to that with 51Cr-labeled cells. Simultaneous testing of two heterologous donor units or testing multiple units in the course of a few days was also feasible. In nine studies (one patient and six healthy controls) no significant elution of the 99mTc was observed over 1 hour.