title: The effect of vitamin C nutriture on complement component C1q concentrations in guinea pig plasma.
abstract: This study shows that guinea pigs fed 100 times the amount of vitamin C needed for growth and for prevention of scurvy have elevated levels of complement component C1q. C1q is a plasma protein rich in hydroxyproline, an amino acid whose biosynthesis requires ascorbate. C1q is essential for host defense against pathogens, both as a component of the classical complement pathway and as an opsonin in the phagocytosis process. We measured C1q in vitamin C-depleted guinea pigs that had been repleted for 4 wks with the following daily doses of ascorbate (mg/100 g body wt): 0.50 (suboptimal), 2.0 (adequate), 10 (ample) and 50 (tissue saturating). We measured C1q in three ways: indirectly by quantifying protein-bound hydroxyproline and directly by hemolytic assay and by immunodiffusion against anti-C1q. Regardless of the method, plasma C1q was 30-50% higher in animals fed tissue-saturating ascorbate than in those fed adequate or suboptimal amounts of the vitamin (p less than 0.05, one-way analysis of variance, least significant difference test). These data confirm and significantly extend earlier work that provided indirect evidence for a relationship between C1q and ascorbate nutriture in the guinea pig. They are consistent with a possible relationship between ascorbate nutriture and host defense.
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000276:immunology; D003166:Complement Activating Enzymes / Q000096:biosynthesis*; D003172:Complement C1 / Q000096:biosynthesis*; D015922:Complement C1q; D006168:Guinea Pigs; D006909:Hydroxyproline / Q000378:metabolism; D005779:Immunodiffusion; D008297:Male; D009752:Nutritional Status
chemical_list: D003172:Complement C1; D015922:Complement C1q; D003166:Complement Activating Enzymes; D001205:Ascorbic Acid; D006909:Hydroxyproline