Defining immune correlates during latent and active chlamydial infection in sheep

Table 1 Cellular response cut-off values for animal selection

Treatment	IFN-γ production cut-off value (pg/mL)	Cellular proliferation cut-off value (counts per minute)
Medium	Above 250	Above 30 000
HEp-2	Above 250	Above 30 000
UV-Chlamydia abortus	Above 1100	Above 70 000
Concanavalin A	Below 450	Below 150 000

For each lymphocyte stimulation assay in vitro treatment, defined cut-offs for animal selection were defined for IFN-γ production (measured on culture supernatant samples collected at 96 h as described in section “Cytokine ELISAs”) and for cellular proliferation (measured for the last 18 h of the 120 h culture as described in section “Cell proliferation assays”). For medium, HEp-2 and UV-Chlamydia abortus antigen the cut-off values for exclusion of outliers were above the values indicated in the IFN-γ production and cellular proliferation. For Concanavalin A, the cut-off values for exclusion of outliers were below the values indicated for IFN-γ and cellular proliferation, respectively.

ISSN: 1297-9716