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. Author manuscript; available in PMC: 2011 Dec 15.
Published in final edited form as: J Immunol Methods. 2010 Oct 1;363(1):42–50. doi: 10.1016/j.jim.2010.09.032

Figure 2.

Figure 2

Effect of storage and shipment conditions on ELISPOT results. Data were derived from cryopreserved PBMC of 12 HIV-infected and 12 uninfected subjects. Cells were cryopreserved at a central laboratory and shipped to the testing laboratories in the conditions indicated on each graph: LN/DI=stored in liquid nitrogen and shipped on dry ice; LN/LN=stored and shipped in liquid nitrogen; 70/DIstored at −70°C and shipped on dry ice. 3, 6, 9, 12 indicate the numbers of weeks of storage at −70°C before shipment. The testing laboratories thawed and assayed samples from each subject in the same run. Results were pooled and presented as means and 95% CI of the entire population, because there were no differences by HIV status (p>0.5). Fig 2a shows that CMV pp65 peptide- stimulated ELISPOT values were not significantly different in LN/LN, LN/DI and 70/DI 3 samples. There was a linear decrease of ELISPOT values with the time of storage at −70°C (p=0.03). Fig 2b shows that CEF peptide-stimulated ELISPOT values were similar in LN/LN, LN/DI and 70/DI 3 samples. There was a trend linear decrease of ELISPOT values with the time of storage at −70°C that did not reach statistical significance (p=0.08). Fig 2c shows that candida- stimulated ELISPOT values were similar in LN/LN, LN/DI and 70/DI 3 samples. There was a linear decrease of ELISPOT values with the time of storage at −70°C (p=0.007).