In the culture medium of some human lymphoblastoid cell lines material is released with the following properties: (a) hemagglutination reaction of IgG-sensitized erythrocytes; (b) enhancement of precipitation of DNA-anti-DNA complexes; (c) inhibition of binding of C1q to immune complexes; (d) inhibition of immune complex binding to lymphocytes; (e) inhibition of antibody-dependent lymphocytotoxicity. The material is not identical with C1q or rheumatoid factor, it is heat resistant (30 min at 56 degrees C); the molecular weight is about 100 000 daltons and it is capable of inhibiting antibody production in vitro. It is suggested that this material consists of Fc receptors spontaneously shed from lymphocyte membranes.

Summary.— In 6 cases of pemphigus (4 pemphigus vulgaris, 1 pemphigus vegetans and 1 pemphigus erythematosus) the direct immunofluorescent method (DIF) revealed various complement factors, as there are Clq, C4 (β1E), β1A and α2D, localized in the intercellular spaces of the epidermis of the skin or mucosa immediately next to the bulla. Immunoglobulin and complement were shown together in the prickle cell layer of the epidermis, while complement staining alone usually could be shown in the intercellular spaces of basal cell layers and in the junctional zone. The possibility that antibody‐mediated complement deposition and/or alternate pathway activation may play a role in the underlying mechanism in pemphigus is discussed.

NATURE 911 + {1 Bison Cattle Bison Fig. 2 . Comparison between tra nsferrin pa t terns In bison and in cattleThere are several explanations why we failed to detect polymorphism in bison transferrins and h::emoglobins. One is that the sample was too small and was not representative of all American buffalo. Another is that genetic variation in these traits was lost during the drastic reduction of the bison populations in the nineteenth century. For example, Owen et al. 8 proposed such an explanation in their discussion of the reasons for the small amount of variation in bison blood groups as detected in tests with cattle blood-typing reagents. But the possibility that bison evolved with little or no genetic variation in such traits cannot be excluded. P erhaps under natural selection mutants at the loci controlling blood groups, transferrins and h::emoglobins are not permitted to accumulate as rapidly as they do under artificial selection.We thank Mr. Julian A . Howard, refuge manager of the

The specijcity of complement antiglobulin agglutinationEvidence was presented in a previous report [14] that the agglutinogen of the so-called "non-gamma globulin" antiglobulin reaction [ l , 2, 16, 151 was dependent upon complement or a protein material fixed nonspecifically in the presence of complement. These observations corroborated earlier work [3] but demonstrated that the sensitivity of agglutination was increased with the use of antisera to human complement. I n addition it was shown that EAC' (optimally sensitized sheep cells complexed with C') could be used as an experimental tool and also as a means of reagent assay.Because of the complexity of C', experiments using total complement activity and specific component activity were designed to elucidate the antiglobulin specificity of antisera to complement. These experiments were based on the current concept of the reaction mechanism of immune hemolysis with guinea pig serum. Investigations of Pillemer [ll] and Leon [6] have shown that a similar reaction mechanism is involved when human serum is the source of complement. Differences were known to exist and some were encountered in the course of this work. These differences were studied and the results are being reported separately [12, 131.