A chimeric porcine reproductive and respiratory syndrome virus 1 strain containing synthetic ORF2-6 genes can trigger T follicular helper cell and heterologous neutralizing antibody responses and confer enhanced cross-protection

Table 3 Responses of Tfh cells, heterologous nAbs and cross-protection among distinct groups

Groups	Pig no	% of Tfh cells^a	Heterologous nAbs^b	Viremia after challenge	Lung lesion
Mock	1	1.39	< 1:8	–	–
	2	2.56	< 1:8	–	–
	3	1.74	< 1:8	–	–
	4	1.13	< 1:8	–	–
	5	1.15	< 1:8	–	–
SD1291 challenge	6	2.26	< 1:8	4–17 dpc	+
	7	4.13	< 1:8	2–21 dpc	+ +
	8	4.44	< 1:8	4–14 dpc	+
	9	4.29	1:8	2–17 dpc	+
	10	2.32	< 1:8	2–21 dpc	+ +
rHLJB1 + SD1291	11	2.77	1:8	2–17 dpc	+
	12	2.35	1:8	4:14 dpc	+
	13	2.27	< 1:8	2–17 dpc	+ +
	14	2.50	< 1:8	4–14 dpc	+
	15	2.61	1:8	4–17 dpc	+
ORF2-6-CON + SD1291	16	5.75	1:8	7–14 dpc	±
	17	6.71	1:16	4–17 dpc	+
	18^c	6.80	1:16	7 dpc	±
	19	4.94	1:8	4–17 dpc	+
	20	4.64	1:8	7–14 dpc	+

^aThe percentages of Tfh cells among CD4 + T cells in the TBLN cohort collected at 21 dpc.
^bThe levels of nAb titres against the SD1291 isolate in serum samples collected at 21 dpc.
^cThe no. 18 pig in the ORF2-6-CON + SD1291 group, which has a high percentage of Tfh cells according to the TBLN, a high titre of heterologous nAbs, and improved cross-protection (short viremia period and mild lung lesion), is highlighted in bold.

ISSN: 1297-9716