Figure 2.

Defining antibody correlates of protection within serum and bronchiolar lavage

(A) Partial least-squares regression (PLSR) model of serum antibody features of vaccinated and boosted non-human primates (NHPs) inversely correlated with viral loads within the lower respiratory tract. Heatmap gradient of viral loads is shown on the right.

(B) PLSR model of BAL antibody features of vaccinated and boosted NHPs inversely correlated with viral loads within the lower respiratory tract. Heatmap gradient of viral loads is shown on the right.

(C) Top serum antibody correlates of protection in the PLSR model.

(D) Top BAL antibody correlates of protection in the PLSR model. Neutralizing antibody titer was not selected as a bona fide correlate in the BAL and was manually plotted in purple for comparison.

(E) Validation of PLSR-selected serum correlates of protection. Viral loads were inversely correlated with (left) neutralizing antibody titer and (right) antibody-dependent natural killer cell activation (ADNKA) as measured by macrophage inflammatory protein 1 beta (MIP1β) production. Spearman’s R values and multiple comparisons adjusted p-values are shown. Trendline is shown with shaded areas being the 95% confidence interval.

(F) Validation of PLSR-selected BAL correlates of protection. Viral loads were inversely correlated with (left) antibody-dependent cellular phagocytosis (ADCP) to BQ.1.1 spike (challenge strain), but not to neutralizing antibody titers. Spearman’s R values and multiple comparisons adjusted p values are shown only for the statistically significant ADCP. Trendline is shown with shaded areas being the 95% confidence interval. See also Figures S3 and S4.