Low molecular proteins in the urine of patients with systemic lupus erythematosus Part 1. Measurement of urinary free light chains

The concentration of urinary free light chains was measured in 61 patients with systemic lupus erythematosus (SLE) by single radial immunodiffusion. The concentration was significantly increased in these patients, and was associated with hypocomplementemia and a high level of antibody to DNA. It also correlated with the clinical disease activity of SLE. It is postulated that increased free light chain in the urine of SLE patients is derived mostly from increased synthesis of light chain rather than from increased breakdown of intact immunoglobulins or decrease of catabolism during renal insufficiency. The measurement of urinary free light chains may offer information for evaluating disease activity in SLE patients

CD154 Costimulated Ovine Primary B Cells, a Cell Culture System That Supports Productive Infection by Bovine Leukemia Virus

Bovine leukemia virus (BLV) is closely associated with the development of B-cell leukemia and lymphoma in cattle. BLV infection has also been studied extensively in an in vivo ovine model that provides a unique system for studying B-cell leukemogenesis. There is no evidence that BLV can directly infect ovine B cells in vitro, and there are no direct data regarding the oncogenic potential of the viral Tax transactivator in B cells. Therefore, we developed ovine B-cell culture systems to study the interaction between BLV and its natural target, the B cell. In this study, we used murine CD154 (CD40 ligand) and γ-chain-common cytokines to support the growth of B cells isolated from ovine lymphoid tissues. Integrated provirus, extrachromosomal forms, and viral transcripts were detected in BLV-exposed populations of immature, rapidly dividing surface immunoglobulin M-positive B cells from sheep ileal Peyer's patches and also in activated mature B cells isolated from blood. Conclusive evidence of direct B-cell infection by BLV was obtained through the use of cloned B cells derived from sheep jejunal Peyer's patches. Finally, inoculation of sheep with BLV-infected cultures proved that infectious virus was shed from in vitro-infected B cells. Collectively, these data confirm that a variety of ovine B-cell populations can support productive infection by BLV. The development of ovine B-cell cultures permissive for BLV infection provides a controlled system for investigating B-cell leukemogenic processes and the pathogenesis of BLV infection