C3 dysregulation due to factor H deficiency is mannan-binding lectin-associated serine proteases (MASP)-1 and MASP-3 independent in vivo.
Bottom Line: Mannan-binding lectin-associated serine proteases 1 and 3 (MASP-1, MASP-3) have been shown recently to contribute to alternative pathway activation by cleaving pro-factor D to its active form, factor D.Co-deficiency of FH and MASP-1/MASP-3 did not ameliorate either the plasma C3 activation or glomerular C3 accumulation in FH-deficient mice.Our data indicate that MASP-1 and MASP-3 are not essential for alternative pathway activation in complete FH deficiency.
Affiliation: Centre for Complement & Inflammation Research, Imperial College London, London, UK.Show MeSH
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Mentions: Using a calcium-free rabbit erythrocyte haemolysis in-vitro assay, AP-mediated cell lysis was readily detectable with wild-type sera (Fig. 5). As expected, no lysis was demonstrable using sera from Cfh–/–.MASP-1/3–/– mice, as these sera are depleted of both C3 and C5 (Fig. 1). However, sera from MASP-1/3–/– mice, in contrast to previous reported in-vitro assays [13,17], did demonstrate lysis, although this was reduced in comparison with that of wild-type mice.
Affiliation: Centre for Complement & Inflammation Research, Imperial College London, London, UK.