Mouse C1q, a subcomponent of the first component of complement, was purified from mouse EDTA plasma by a combination of precipitation with polyethyleneglycol, affinity chromatography on IgG-Sepharose, ion exchange chromatography and molecular sieving. Mouse C1q was compatible with human C1q in the sense that it shows C1 hemolytic activity by the combination with human C1-r and C1-s. The molecul...

Accumulating evidence from mice expressing ALS-causing mutations in superoxide dismutase (SOD1) has implicated pathological immune responses in motor neuron degeneration. This includes microglial activation, lymphocyte infiltration, and the induction of C1q, the initiating component of the classic complement system that is the protein-based arm of the innate immune response, in motor neurons of...

C1q-binding ability may indicate the clinical relevance of de novo donor-specific anti-HLA antibodies (DSA). This study investigated the incidence and risk factors for the appearance of C1q-binding de novo DSA and their long-term impact. Using Luminex Single Antigen Flow Bead assays, 346 pretransplant nonsensitized kidney recipients were screened at 2 and 5 years after transplantation for de no...

OBJECTIVES De novo donor-specific HLA antibodies (DSA) are associated with allograft rejection and allograft loss. However, not all DSA are equally detrimental to allograft function. The ability to activate complement may be an important factor differentiating clinically relevant DSA from nonrelevant DSA. The C1q assay detects a subset of HLA antibodies that can fix complement. This study aimed...

The in vivo metabolism of radioiodinelabeled C1q was determined in patients with hypogammaglobulinemia, multiple myeloma, systemic lupus erythematosus (SLE), and in healthy controls. Marked differences in metabolic behavior were observed with a much more rapid disappearance of plasma radioactivity in patients as compared with controls. Estimated plasma volumes at 10 min after injection (time 0)...

The consolidation of single antigen beads (SAB-panIgG) assay in the detection of preformed anti-human leukocyte antigen (HLA) antibodies has improved transplantation success. However, its high sensitivity has limited the allograft allocation for sensitized patients, increasing their waiting time. A modification of the standard SAB-panIgG assay allows the detection of that subset of antibodies c...

Human C1q when injected directly into hippocampus and cortex of doubly transgenic APP1PS1 mice results in the increase of Congo red–positive fibrillar deposits. Although there was no significant change in overall area stained for Ab total, qualitatively it appeared that there was less diffuse Ab in C1q-treated mice versus vehicle. There was no apparent change in astroglial or microglial activat...

Hereditary complete deficiency of complement component C1q is associated with a high prevalence of systemic lupus erythematosus and increased susceptibility to severe recurrent infections. An 11-year-old girl was screened for immunodeficiency due to a history of recurrent meningitis and pneumonia. Immunologic studies revealed absence of classic pathway hemolytic activity and undetectable levels...

Bachground: C1q is assembled in 1:1:1 ratio from three subunits demanding synchronized expression of three genes in a cluster – C1q deficiency causes lupus Results: A PU.1/IRF8-stimulated `core promoter’ appears to exist in this gene cluster Conclusion: A core promoter helps synchronize three C1q gene transcription Significance: This helps explain the highly conserved clustering of three C1q ge...

The heptose-less mutant of Escherichia coli, D31m4, bound complement subcomponent C1q and its collagen-like fragments (C1qCLF) with Ka values of 1.4 x 10(8) and 2.0 x 10(8) M-1 respectively. This binding was suppressed by chemical modification of C1q and C1qCLF using diethyl pyrocarbonate (DEPC). To investigate the role of lipopolysaccharides (LPS) in this binding, biosynthetically labelled [14...