A defect of B-lymphocyte transport of aggregated HGG into germinal centres in NZB and NZB x NZW F 1 hybrid mice.

Previous experiments have shown (i) that the localization of intravenously injected heat aggregated human γ-globulin (HGG) in the germinal centres of normal mice provides a model for studying the natural uptake of circulating immune complexes in these areas, and (ii) that the aggregated HGG is carried into germinal centres by lymphocytes which have receptors for altered γ-globlin. Evidence from thymus-cell depletion experiments is now presented which suggests that the lymphocytes concerned are bone-marrow-derived B cells. Defective localization was found in NZB and NZB × NZW F1 hybrids at different ages and the onset of the autoimmunity and the appearance of histological abnormalities in the spleen. As disease develops it progresses to a complete inability to localize complexes in germinal centres. It is concluded that a functional defect of the bone marrow-derived lymphocyte population exists in these mice.