Table 4.

.Effects of antiretroviral use, viral load, and virus clade on IgG3 antibody half-life.

			Half-life (days)
Antibody Response	Model	Estimate type	Estimate	95% CI	P value
IgG3 p55	Exponential decay model	Overall	59.91	51.05–68.74	0.0092
	Viral load only model	Low	49.09	36.19–61.99
		High	77.24	60.85–93.63
	ART use only modela	No	22.10	17.57–26.65	<0.0001
		Yes	47.40	44.37–50.44
	Location only modelc	USA	13.59	0.70–26.49	0.0921
		Africab	71.71	56.42–87.01
IgG3 p66	Exponential decay model	Overall	52.14	44.67–59.61	0.0119
	Viral load only model	Low	42.41	33.39–51.43
		High	62.7	49.96–75.44
	ART use only modela	No	50.11	44.09–56.12	<0.0001
		Yes	20.54	18.04–23.05
	Location only modelc	USA	51.07	40.20–61.93	0.0146
		Africa	74.66	60.23–89.10
IgG3 p31	Exponential decay model	Overall	26.86	23.18–30.55
	Viral load only model	Low	25.04	19.84–30.23	0.2394
		High	29.47	23.67–35.27
	ART use only modela	No	33.12	23.33–42.92	0.0046
		Yes	20.44	16.84–24.05
	Location only modelc	USA	33.08	22.9–43.26	0.0039
		Africa	40.57	28.50–52.64
IgG3 gp41	Exponential decay model	Overall	28.99	23.56–34.42
	Location only modelc	USA	70.16	42.16–98.15	0.0001
		Africa	24.96	19.13–30.78
IgG3 gp120	Exponential decay model	Overall	17.43	16.58–18.28	0.0143
	Viral load only model	Low	11.65	7.23–16.06
		High	17.57	16.83–18.30
	ART use only modela	No	17.49	17.15–17.83	<0.0001
		Yes	11.33	10.41–12.26
	Location only modelc	USA	17.50	17.05–17.94	<0.0001
		Africa	529.95	183.6–876.3

ART, antiretroviral therapy; CI, confidence interval.

^aUSA participants only.

^bMalawi/South Africa, predominantly clade C.

^cSamples prior to start of ART only.