Comparative analysis of the profiles of IgG subclass-specific responses to Plasmodium falciparum apical membrane antigen-1 and merozoite surface protein-1 in naturally exposed individuals living in malaria hypoendemic settings, Iran

Table 2 Comparative analysis of the level of IgG and subclass antibodies to rPfAMA-1 and rPfMSP-1 ₁₉ antigens among individuals with patent P. falciparum infection from south-eastern Iran

Antigen	Mean OD ₄₉₀ ± SD
Antigen	IgG	IgG1	IgG2	IgG3	IgG4
PfAMA-1	1.096 ± 0.393	1.307 ± 1.001	0.232 ± 0.027	0.938 ± 0.436	0.502 ± 0.144
Frequency of responders (%)	88 (87.1)	88 (87.1)	9 (8.9)	36 (35.6)	4 (4)
Cut-off	0.284	0.273	0.2	0.37	0.25
PfMSP-1 ₁₉	1.467 ± 0.619	1.654 ± 0.802	0.404 ± 0.191	0.936 ± 0.430	0.467 ± 0.088
Frequency of responders (%)	85 (84.2)	84(83.2)	10 (9.9)	44 (43.6)	4 (4)
Cut-off	0.323	0.319	0.215	0.357	0.2
P value (Spearman’s correlation test)	<0.0001	< 0.0001	< 0.0001	< 0.0001	< 0.0001

The mean OD₄₉₀ nm value was considered as a measure of the anti-PfAMA-1 or -PfMSP-1₁₉ -specific antibody responses of each serum sample by ELISA assay. The cut-off values were calculated by mean ODs of normal human sera (n = 30) out of malaria- endemic areas plus 3 standard deviation (SD). There was a significant correlation among the mean ODs of IgG, IgG1, IgG2, IgG3, and IgG4 to PfAMA-1 and PfMSP-1₁₉ antigens (IgG, r = 0.603, P <0.0001, IgG1, r = 0.593, P < 0.0001; IgG2, r = 0.433, P < 0.0001; IgG3, r = 0.457, P < 0.0001; and IgG4, r = 0.464, P < 0.0001; Spearman’s correlation test).

ISSN: 1475-2875