The complement component C4 of mammals

The complement component C4 of mammals.

Human complement component C4 is coded by tandem genes located in the HLA class III region. The products of the two genes, C4A and C4B, are different in their activity. This difference is due to a degree of 'substrate' specificity in the covalent binding reactions of the two isotypes. Mouse also has a duplicated locus, but only one gene produces active C4, while the other codes for the closely ...

TaqI RFLP polymorphism of the ovine complement component C4 gene.

Protocol: Reactions were performed as described (2) using 1 ng of DNA and 100 pmoles of each primer. DNA was amplified for 20 cycles using a Perkin Elmer Cetus DNA Thermal Cycler: denaturation, 94°C, 1 min; annealing, 60°C, 1 min; and extension, 70°C, 1.5 min. Ten /il of the reaction was analyzed directly on a 2.5 % NuSieve GTG agarose gel run in Tns-borate buffer. The amplified DNA fragments v...

Effect of thiol compounds on human complement component C4.

Thiol compounds have been investigated as inhibitors of the covalent binding reaction of human complement protein C4 using Sepharose-C1s as a combined activating and binding surface. o- and p-substituted aminothiophenols are equally effective inhibitors, whereas the m-substituted compound is a less potent inhibitor. The anti-hypertensive drug captopril is also shown to inhibit the covalent bind...

Immunity in C4-Deficient Mice Component C4 Can Restore Humoral Macrophage-Derived Complement

The origin of the very variable haemolytic activities of the common human complement component C4 allotypes including C4-A6.

The human complement component C4 occurs in many different forms which show big differences in their haemolytic activities. This phenomenon seems likely to be of considerable importance both physiologically and pathologically. C4 is coded by duplicated genes between HLA-D and HLA-B loci in the major histocompatibility complex in man. Several fold differences in haemolytic activity between produ...