Fig. 3.

Cross-linking surface-bound C1q results in TNF-α secretion from T cells. T cells were preincubated with either C1q immune complexes (‘C1qIC’) or purified human C1q followed by polyclonal anti-C1q antibody (‘C1q + anti-C1q’) as described in the Methods section. TNF-α secretion was induced under both experimental conditions. Neither monomeric C1q (‘C1q’) nor polyclonal anti-C1q antibody (‘anti-C1q’) induced TNF-α secretion. , T cells; , C1q; , C1q + anti-C1q; ▪, C1qIC; □, anti-C1q.