Simian immunodeficiency virus (SIV) envelope quasispecies transmission and evolution in infant rhesus macaques after oral challenge with uncloned SIVmac251: increased diversity is associated with neutralizing antibodies and improved survival in previously immunized animals

Table 1 Experimental design and summary of outcome.

Immunization^a groups and animal numbers	sex	MHC I alleles^b		Variant Pattern^c	Week 1 Plasma Viral RNA^d	Time of euthanasia (wks)^e
		MamuA*01	MamuB*01
*Group 1 Unvaccinated + SIVmac251*
31319	M	+	+	A	4.3 × 10⁷	13
31321	M	+/-	-	A	1.7 × 10⁸	28
31322	F	+/-	+/-	A	1.2 × 10⁸	14
31325	M	+	+	B	5.5 × 10⁶	12
31608^f	F	+/-	+/-	C	7.5 × 10⁵	11
*Group 2 MVA-SIVgpe only*
31480	M	-	-	na	na	na
31488	M	+/-	+/-	na	na	na
*Group 3 MVA-SIVgpe + SIVmac251*
31378	M	-	-	A	4.8 × 10⁵	28^g
31533	M	+/-	-	A	3.7 × 10⁷	26
31540	M	+/-	-	C	2.5 × 10⁷	28^g
31542	M	-	-	B	3.3 × 10⁵	26
*Group 4 MVA-SIVgpe with Mat. Abs. + SIVmac251*
31526	M	+/-	+/-	A	6.9 × 10⁷	27
31732	F	-	+/-	A	1.8 × 10⁷	19
31833	F	+/-	-	A/C	4.5 × 10⁵	28^g
31856	F	-	+/-	B	1.4 × 10⁶	28^g
*Group 5 SIVmac1A11 + SIVmac251*
31777	F	+/-	-	A	6.8 × 10⁷	28^g
31778	F	-	-	B	4.7 × 10⁵	28^g
31779	F	-	-	A	2.3 × 10⁸	28^g
31780	F	+/-	-	A	9.9 × 10⁷	28^g

^a Vaccine administered in 2 doses, at birth and 3 weeks of age. Animals of groups 1, 3, 4 and 5 were challenged orally at 4 weeks of age with SIVmac251-5/98.
^b The presence of the MHC type I alleles of MamuA*01 and MamuB*01 is indicated as + (present, but unknown whether homozygous or heterozygous), +/- (heterozygous based on known haplotypes of parents), and - (homozygous for absence of particular allele).
^c Variants in plasma at one week post-challenge with SIVmac251-5/98.
^d Copies of viral RNA per ml one week after challenge with SIVmac251-5/98, as measured by bDNA assay.
^e Age (weeks) at time of euthanasia.
^f Infant 31608 was born to an SIVmac251-infected macaque, and thus had maternal anti-SIV antibodies, but no virus was detected in this infant at 4 weeks of age.
^g indicates that animal was clinically stable at time of experimental euthanasia at 28 weeks of age; all other SIV-infected animals were euthanized due to life-threatening disease prior to or at 28 weeks of age. The animals of group 2 were not euthanized. na indicates not applicable.

ISSN: 1743-422X