Cytology and histology of haemopoietic cell transplantation under the influence of antilymphocyte serum (ALS) in mice. I. The in vivo effect of antilymphocytic globulin on haemopoietic tissue

C57BL/6J mice were treated with ALS, ALG, normal rabbit serum (NRS) or IgG of the rabbit for a period of 6 days. To study the xenogeneic antigenicity of ALG and its antilymphocytic effect separately, half the mice were made tolerant to IgG of the rabbit. While a short schedule of injections of ultracentrifuged IgG induced tolerance to IgG, this tolerance was eliminated by the subsequent treatment with ALG. A prolonged injection schedule over 44 days did, however, lead to a tolerance which persisted after ALG treatment. [131I]IgG elimination proved to be a more sensitive control of tolerance than immunodiffusion.