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PubMed1989

Serological survey of complement factor H in common laboratory and wild mice: a new third allotype.

Antigenic specificities of complement factor H from mice were studied serologically. In addition to previously reported allotypes, referred to as H.1 and H.2, a new allotype of complement factor H, H.3, was identified in the BFM/2Ms strain derived from European wild mice. Using three different alloantisera raised against the various mouse factor H allotype, a serological survey of the common laboratory strains and wild-derived strains of Mus musculus and its relatives, Mus spretus, Mus spretoides, and Mus spicilegus was carried out. All of the common laboratory strains examined in this survey had the H.1 allotype except for STR/N which had H.2. The geographical distributions of factor H allotypes in M. musculus were specific to the subspecies. Mice derived from Mus musculus domesticus and Mus musculus castaneus had the H.1 allotype. Mice derived from M. m. musculus, Mus musculus bactrianus, and Mus musculus molossinus had the H.2 allotype. Only BFM/2Ms and BFM/1Mpl strains derived from M. m. domesticus had the novel H.3 allotype. Sera of mice from strains derived from M. spretoides and M. spicilegus cross-reacted with H.2-specific antiserum, and those from M. spretus cross-reacted with H.3-specific antiserum.

Alleles↗
PubMed1988

Combined homozygous factor H and heterozygous C2 deficiency in an Italian family.

Three of four children in a family have homozygous (less than 1% of normal) deficiency of factor H of the complement system and both parents, who are first cousins, are heterozygous for the same defect. The father and two of the H-deficient siblings also have a partial C2 deficiency. One of the children with combined deficiencies is affected by systemic lupus erythematosus with nephritis. No increased susceptibility to infections has been observed in the family. H deficiency is inherited in an autosomal codominant manner and is independently transmitted from C2 deficiency and HLA haplotypes. In the homozygous state it is associated with very low serum concentrations of B and C3, barely demonstrable as activated molecules. C5 is greatly reduced (less than 5%). Also, properdin and C6-9 are decreased. The findings in this family demonstrate that the occurrence of systemic lupus erythematosus in one of the children affected by a combined deficiency of factor H and C2 raises the question whether this pathology is related to the complete factor H or to the heterozygous C2 deficiency. Complete H deficiency is not necessarily accompanied by overt illness.

Child↗
PubMed1982

Partial H (beta 1H) deficiency and glomerulonephritis in two families.

H (beta 1H) controls the C3b amplification loop by its ability to displace Bb from the alternative pathway convertase, C3b,Bb, and acts as a cofactor with I (C3b inactivator) to produce inactive C3b. Serum C3 levels are dependent to a large extent on the levels of H and I. Partial H deficiency was found in two families. The index case in Family 1 had vasculitis, thrombocytopenia, proteinuria, and depressed serum H and C3 levels. The index case in Family 2 had depressed serum H and B (Factor B) levels and IgA nephropathy which progressed to renal failure. His sister also had IgA nephropathy and depressed serum H and C3 levels. The depressed serum C3 level, B level, and H level could be responsible for the development of the immune diseases found in some members of these families.

Adolescent↗
PubMed1992

A new biological activity of the complement factor H: identification of the precursor of the major macrophage-chemotactic factor in delayed hypersensitivity reaction sites of guinea pigs.

The guinea pig complement factor H(FH) and the plasma precursor(PMCFS-1) of the major monocyte-chemotactic factor(MCFS-1) found in the skin site of delayed hypersensitivity reaction(DHR) induced in the guinea pigs were compared in the antigenicity and the function. Both anti-FH-IgG and anti-MCFS-1-IgG formed a single precipitation line against FH, PMCFS-1, MCFS-1 and guinea pig plasma, and these lines fused one another without any spur formation. The inhibition activity of FH for C3bBb was absorbed by anti-MCFS-1-F(ab')2 in a dose-dependent manner. PMCFS-1 inhibited C3bBb activity dose-dependently as FH. These results show that FH is identical to PMCFS-1 and imply that FH, converted to MCFS-1 plays as a monocyte-chemotactic factor in the site of DHR.

Animals↗
PubMed1984

The mechanism of cell-mediated cytotoxicity. IV. K-76 COONa, which inhibits the activity of Factor I and of C5, inhibits early events in cytotoxic T-lymphocyte-mediated cytolysis and in T-lymphocyte activation.

K-76 COONa is a derivative of a fungal product which blocks complement (C)-mediated lysis by combining with C5 and preventing its activation to C5b. K-76 COONa can also combine with Factor I and inhibit its ability to hydrolyze C3b to iC3b. The inclusion of K-76 COONa at concentrations similar to those which inhibit C lysis blocked both murine cytotoxic-T-lymphocyte (CTL)-mediated lysis (CML) and the lectin-stimulated proliferative response of murine and human T lymphocytes. A modified cation pulse procedure has been used to determine which phases of CML were most sensitive to the drug. K-76 COONa was inhibitory when it was added to CML prior to the early Mg+2-dependent binding phase, but was much less effective when it was added at any time after the formation of CTL-target conjugates. The principal effect of the drug on the proliferative response was also exerted during an early phase of the response. K-76 COONa did not appreciably decrease the production of T-cell growth factor (TCGF), but it did inhibit the induction of TCGF receptor expression by both functional criteria, i.e., induction of responsiveness to TCGF, and by morphological criteria, i.e., the expression of the Tac antigen. Later events, such as the TCGF-dependent proliferation of cycling T cells, were less sensitive to the drug. Evidence is discussed suggesting that molecules similar to Factor I and to C3 may be involved both in the early events of CML and of T-lymphocyte activation.

Cells, Cultured↗
PubMed1987

Ixodes dammini: salivary anti-complement activity.

Saliva of the tick Ixodes dammini prevents hemolysis of rabbit erythrocytes by the human alternative pathway of complement. Deposition of C3b to activating surfaces and concomitant C3a release are inhibited. C3b deposition to activating surfaces is inhibited regardless the origin (humans, rat, mouse, guinea pig, and hamster) of the serum. The inhibitor elutes as a single peak upon gel filtration, with an apparent molecular weight of 49,000. Salivary anti-complement may contribute to successful feeding of I. dammini in their natural hosts.

Animals↗
PubMed1981

beta 1H-hemagglutination assay: a highly sensitive test for human beta 1H and its uses.

Particle-bound human C3b (EAC14oxy23b) serves as the carrier for the detection of biologically active human beta 1 H by IgG-anti-beta 1H. This hemagglutination assay is highly sensitive (greater than or equal to 2 p of beta 1H/40 microliters), easy to perform, rapid, highly reproducible, and needs no expensive laboratory equipment. All reagents are commercially available. The correlation of the beta 1H-hemagglutination assay is applicable for the detection of beta 1H in various buffer systems and may be used for the detection of beta 1H in serum or fractions thereof. It is a very useful tool for the detection of trace contamination of beta 1H in serum fractions, particularly in complement preparations.

Animals↗
PubMed1985

Isolation of human complement factors C3, C5 and H.

An improved method for simultaneous purification of complement factors C3, C5 and H from human plasma has been developed. Using an initial batch separation technique with QAE-Sephadex, followed by chromatography on SP-Sephadex and gel filtration in Sephadex G-200, 600 mg of highly pure C3 can be prepared from 1600 ml of plasma. Simultaneously about 70 mg of highly pure factor H and 30 mg of C5 are obtained by chromatography of post SP-Sephadex material on DEAE-Sephacel. A small amount of C3 in the C5 pool is removed by anti-C3-Sepharose. By maleylation or citraconylation of reduced and alkylated C3, the constitutive polypeptide chains are modified in a way that made them separable by ion exchange chromatography.

Chromatography, Gel↗