Preparation and properties of a cytotoxic monoclonal rat anti-mouse Thy-1 antibody.

A hybrid cell line secreting a cytotoxic rat IgM antibody with specificity for both the 1 and 2 alleles of mouse Thy-1 was selected. The fusion was between rat spleen cells immunised to SBA spleen cell plasma membranes and the rat myeloma cell line 210RCY3-Ag123. The cell line can be propagated in Lou-strain rats to yield large volumes of antibody-containing ascites with a cytotoxic titre of 10(6)-10(7) for peripheral T cells. The antibody is relatively stable and can be used for indirect fluorescence assays in conjunction with a fluorochrome (e.g. fluorescein)-coupled goat anti-rat immunoglobulin (pre-absorbed on mouse immunoglobulin). More simply, it can be directly conjugated to a fluorochrome and used in association with an appropriately absorbed goat anti-mouse Ig coupled with a contrasting and different fluorochrome (e.g. rhodamine) to allow simultaneous enumeration of both T and B lymphocytes.