Beta 2-microglobulin is selectively associated with H-2 and TL alloantigens on murine lymphoid cells.

We have used a rabbit antiserum prepared against purified rat beta2-microglobulin to immunoprecipitate molecules from lysates of radioiodinated murine thymocytes and splenocytes. All the molecules that are reactive with this serum have subunits of 44,000 and 12,000 and can be identified as H-2 and TL antigens. Thus, the anti-beta2mu serum can deplete lysates of the majority of the TL and H-2 atigens which can be subsequently recognized by alloantisera. If TL and H-2 are precipitated from the lysates before the addition of anti-beta2mu, no beta2mu-reactive molecules remain. Our results indicate that Ia antigens cannot be depleted from the lysates with anti-beta2mu. The studies also suggest that TL and H-2 heavy chains can exist as both monomers and dimers. These observations are discussed with regard to previous studies concerning the native structure of H-2 and TL antigens.