IFNγ neutralization also increases AM infection.

<p><b>a.</b> C57BL/6 mice given IFNγ neutralizing antibody (αIFNγ), depleted of CD4⁺ T cells (αCD4) or left untreated (control), were given MuHV-4 i.n. (10⁴ p.f.u.). 9d later lungs were plaque assayed for infectious virus, and mediastinal LN (MLN) and spleens infectious center assayed for latent virus. Bars = mean ± SEM of 6 mice per group. Dashed line = assay sensitivity limit. <b>b.</b> Mice were treated as in <b>a</b>. 9d later lung sections were stained for viral lytic antigens (MHV) plus CD68, PDP or CD4. Quantitation of staining showed that αIFNγ mice had significantly more MHV⁺ AEC1 and AM than controls, with AM accounting for a significantly greater proportion of all MHV⁺ cells. <b>c.</b> Examples of staining as quantitated in <b>b</b>. Nuclei were stained with DAPI. Filled arrows show example MHV⁺ AM. Red / green co-localization appears as yellow. The open arrow shows a CD4⁺ T cell adjacent to an infected cell. This was commonly observed after IFNγ neutralization. <b>d.</b> Mice were depleted of CD8⁺ T cells (αCD8), given also IFNγ neutralizing (αCD8αIFNγ) or CD4⁺ T cell depleting antibodies (αCD8αCD4), and all mice were then infected with MuHV-4 i.n. (10⁴ p.f.u.). 9d later infectious virus was plaque assayed in noses and lungs. Bars = mean ± SEM of 6 mice per group. Dashed line = assay sensitivity limit. αCD8αIFNγ significantly increased titers above αCD8 and αCD8αCD4 significantly increased titers above αCD8αIFNγ (p<0.01). <b>e.</b> Lung sections of mice treated as in <b>d</b> were stained for MHV and cell type markers (CD68, PDP). Cells were counted for 3 fields of view per section, across 3 sections each of 3 mice per group. Bars = mean ± SEM counts of individual mice. αCD4αCD8 significantly increased CD68⁺ infected cell numbers over αCD8 alone (p<0.05). αIFNγ/αCD8 did not (p>0.2).