Detection of recombinant human EPO administered to horses using MAIIA lateral flow isoform test.

Doping of horses with recombinant human erythropoietin (rHuEPO) to illegally enhance their endurance capacity in horseracing has been reported during the last years. This leads to increased blood viscosity which can result in sudden death and is of concern for the horse welfare. Additionally, the horse can start production of rHuEPO antibodies, which cross-reacts with endogenous equine EPO and can lead to severe anaemia and even death. In this study, a novel micro-chromatographic method, EPO WGA MAIIA, has been tested for the capability in plasma and urine samples to detect administration of erythropoiesis-stimulating agents, like the rHuEPO glycoprotein varieties Eprex and Aranesp, to horses. After administration of 40 IU Eprex kg(-1) day(-1) to seven horses during 6 days, the presence of Eprex in horse plasma was detected up to 2-5 days after last injection. In urine samples collected from two horses, Eprex was detected up to 3 days. A single injection of Aranesp (0.39 µg/kg) was detected up to 9 days in plasma and up to 8 days, the last day of testing, in the urine sample. The LC-FAIMS-MS/MS system, with 1 day reporting time, confirmed the presence of Eprex up to 1 day after last injection for six out of seven horses and the presence of Aranesp up to 5 days after last injection in plasma samples. The MAIIA system showed to be a promising tool with high sensitivity and extremely short reporting time (1 h).

Marginal zone B cells are naturally reactive to collagen type II and are involved in the initiation of the immune response in collagen-induced arthritis.

Antibodies against type II collagen (CII) are essential for development of collagen-induced arthritis (CIA), but how and where the B-cell response to CII is initiated is not fully known. We show here that naive DBA/1 mice display naturally reactive IgM and IgG anti-CII producing B cells prior to immunization. The CII-reactive B cells were observed in the spleen and recognized as marginal zone (MZ) B cells. After CII immunization, CII-specific B cells expanded rapidly in the spleen, in contrast to the lymph nodes, with the initial response derived from MZ B cells and later by follicular (FO) B cells. This was evident despite that the MZ B cells were subject to stringent tolerance mechanisms by having a greater Fc gamma receptor IIb expression than the FO B cells. Further, the MZ B cells migrated to the FO areas upon immunization, possibly providing antigen and activating FO T cells and subsequently FO B cells. Thus, around CIA onset increased numbers of IgG anti-CII producing FO B cells was seen in the spleen, which was dominated by IgG2a- and IgG2b-positive cells. These data demonstrate that CII-reactive MZ B cells are present before and expand after CII immunization, suggesting an initiating role of MZ B cells in the development of CIA.