TABLE 3.

Flow cytometry-based analysis of complement C3 deposition on the surface of pneumococci in the presence of anti-PspA^hkR36A MAbs^a

Strains (clade)	GMFI (fold change) for:
	Negative controlb	Positive controlc	IgG1 isotype control	B3D12d	B3H8d	L5C8d	L5F10d	M4F4d	P1E11d	IgG2a isotype control	P2A4e	P2B5e
BG8838 (1)	4.5	16.6	15.3	29.6	30.3	24.0	14.4	71.7f	233.0f	12.3	39.4f	106.0f
WU2 (2)	3.0	3.4	3.2	3.8	20.5f	3.4	5.2	482.0f	442.0f	3.6	320.0f	391.0f
D39 (2)	5.5	7.1	7.0	418.0f	12.9	516.0f	511.0f	568.0f	523.0f	6.1	429.0f	384.0f

^aThe PspA family 1-expressing strains BG8838 (clade 1) and WU2 and D39 (clade 2) were incubated with either anti-PspA^hkR36A or a matched isotype control MAb. The bound complement C3 was detected by flow cytometry using anti-human C3 antibody followed by the appropriate FITC-conjugated secondary antibody.

^bPneumococci were incubated with anti-human complement C3 antibody followed by the FITC-conjugated secondary antibody.

^cPneumococci were incubated with 10% pooled normal human serum in Hanks' balanced salt solution followed by anti-human C3 antibody and the FITC-conjugated secondary antibody.

^dThese anti-PspA^hkR36A MAbs are of the IgG1 isotype.

^eThese anti-PspA^hkR36A MAbs are of the IgG2a isotype.

^fGMFI values greater than or equal to twice the value obtained with the corresponding isotype control were considered significant.