Figure 4. Allogeneic splenocyte transfer followed by inhaled LPS leads to preferential expansion of CD8 T cells.

Rag1^−/− mice received a transfer of allogeneic (Allo) or syngeneic (Syn) splenocytes and underwent daily exposures to aerosolized LPS for 5 days starting 1 week after splenocyte transfer. Mice were euthanized 72 hours after the last LPS exposure and lung lymphocytes were analyzed using flow cytometry and immunohistochemistry. Representative flow cytometry plots for SynLPS and AlloLPS show the gating of (A) small cells among all cells, (B) CD3 versus CD4 gating among small cells, (C) CD3 versus CD8 gating among small cells where the percentage of CD8 T cells is higher in AlloLPS (17.1%) compared to SynLPS (5.24%), and (D) gating of CD49⁺ NK cells among small cells. (E) Lung immunohistochemical staining for the CD3 antigen demonstrates that CD3 T cells represent the majority of cells in the infiltrates around airways and blood vessels in AlloLPS and SynLPS mice. (F) By flow cytometry, there is no difference in numbers of total cells between the lungs of AlloLPS and SynLPS mice. (G) Total CD3 T cells or B cells are also not different between the lungs of AlloLPS and SynLPS mice. It is apparent, however, that CD3 T cells are much more abundant than B cells in both AlloLPS and SynLPS. (H–I) Further analysis of T cells by flow cytometry shows that CD8 T cells are significantly increased in the lungs of AlloLPS mice as compared to SynLPS (p = 0.03), while CD4 T cells are unchanged. (J) NK cell numbers, as identified by CD49b expression, are not significantly different between AlloLPS and SynLPS mice. Numeric data represent the average +/− SEM and * = p<0.05. Data have been replicated in 2 independent experiments.