Table 1.

Correlation between magnitude of intestinal and systemic IFN-γ producing T cell responses and protection rates against HRV diarrhea

Group	Protection rate against HRV diarrhea^a	Mean frequencies of IFN-γ producing T cells in ileum			Mean frequencies of IFN-γ producing T cells in spleen
		IFN-γ+CD4+ T cells	IFN-γ+CD8+ T cells	IFN-γ+CD4+CD8+ T cells	IFN-γ+CD4+ T cells	IFN-γ+CD8+ T cells	IFN-γ+CD4+CD8+ T cells
VirHRV	87%^A^b	1.40^A^c	1.49^A	nd^d	0.11^BC	0.10^BC	nd
AttHRV-2/6VLP	71%^A	0.82^AB	1.07^A	0.76^A	0.51^A	0.75^A	0.45^A
AttHRV3x	62%^A	0.28^B	0.07^B	0.18^AB	0.61^AB	0.38^B	0.38^A
AttHRV2x	34%^AB	0.18^B	0.07^AB	0.15^AB	0.28^AB	0.01^C	0.42^A
Control	0%^B	0.02^C	0.01^B	0.01^B	0.05^C	0.14^BC	0.02^B

Correlation coefficient^e		r=1.0 p < 0.0001	r = 0.97468 p = 0.0048	r=1.0 p < 0.0001	r = 0.3000 p = 0.6238	r = 0.2000 p = 0.7471	r = 0.8000 p = 0.2000

At PID 28, subsets of pigs (7–25 pigs/group) were challenged orally with ∼10⁶ ID₅₀ of VirHRV. Rectal swabs were collected and fecal scores were observed from post-challenge day (PCD) 1–6 for assessment of diarrhea (fecal scores of 0, normal; 1, pasty; 2, semi-liquid; and 3, liquid). Scores of greater or equal to 2 were considered as diarrhea. The pigs were considered as completely protected against diarrhea upon challenge with VirHRV only when they did not have diarrhea during the entire observation period. Control pigs were inoculated with diluent or ISCOM matrix only and challenged with VirHRV. Protection rate = [1−(percentage of VirHRV-inoculated or vaccinated pigs in each group with diarrhea/percentage of control pigs with diarrhea)]×100. Protection data from present study and previously published studies [3–6] were combined.

Numbers with different superscript capital letters differ significantly (Fisher's exact test, p < 0.05).

Mean frequencies in the same column with different superscript capital letters differ significantly (Kruskal–Wallis test, p < 0.05).

nd, not determined.

Correlation coefficient between protection rates and mean frequencies of IFN-γ producing T cells (Spearman's correlation).