Cross-reactive immunity against influenza viruses in children and adults following 2009 pandemic H1N1 infection.

UNLABELLED: 2009 H1N1 pandemic influenza (A(H1N1)pdm09) virus infected large numbers of people worldwide. Recent studies suggest infection with A(H1N1)pdm09 virus elicited cross-reactive anti-hemagglutinin (HA) memory B cell response to conserved regions of HA. However, the breadth and magnitude of cross-reactive immunity in children and adults following A(H1N1)pdm09 infection are unknown. METHODS: We investigated serum anti-HA immunity to a number of group-1 and -2 viruses in children and adults using hemagglutination inhibition (HAI), enzyme-linked immunosorbent assay and virus neutralization assay. RESULTS: Applying hemagglutination inhibition (HAI) titers ⩾40 against A(H1N1)pdm09 as threshold of sero-positivity, we observed significantly higher levels of anti-HA antibodies to a number of virus subtypes, including those neutralizing H5N1, in subjects with HAI titer ⩾40 than those with HAI <40. Adults demonstrated broader and stronger cross-reactive anti-HA antibodies than children, including cross-reactive anti-HA1 and -HA2 antibodies. By comparison, individuals with serologic evidence of recent exposure to seasonal H1N1 or H3N2 did not show such broad cross-reactive immunity. CONCLUSION: Our results suggest individuals exposed to A(H1N1)pdm09 virus developed a broad and age-associated cross-reactive anti-HA immunity which may have important implications for future vaccination strategies to enable protection against a broader range of influenza viruses.

Dsh homolog DVL3 mediates resistance to IGFIR inhibition by regulating IGF-RAS signaling.

Drugs that inhibit insulin-like growth factor 1 (IGFI) receptor IGFIR were encouraging in early trials, but predictive biomarkers were lacking and the drugs provided insufficient benefit in unselected patients. In this study, we used genetic screening and downstream validation to identify the WNT pathway element DVL3 as a mediator of resistance to IGFIR inhibition. Sensitivity to IGFIR inhibition was enhanced specifically in vitro and in vivo by genetic or pharmacologic blockade of DVL3. In breast and prostate cancer cells, sensitization tracked with enhanced MEK-ERK activation and relied upon MEK activity and DVL3 expression. Mechanistic investigations showed that DVL3 is present in an adaptor complex that links IGFIR to RAS, which includes Shc, growth factor receptor-bound-2 (Grb2), son-of-sevenless (SOS), and the tumor suppressor DAB2. Dual DVL and DAB2 blockade synergized in activating ERKs and sensitizing cells to IGFIR inhibition, suggesting a nonredundant role for DVL3 in the Shc-Grb2-SOS complex. Clinically, tumors that responded to IGFIR inhibition contained relatively lower levels of DVL3 protein than resistant tumors, and DVL3 levels in tumors correlated inversely with progression-free survival in patients treated with IGFIR antibodies. Because IGFIR does not contain activating mutations analogous to EGFR variants associated with response to EGFR inhibitors, we suggest that IGF signaling achieves an equivalent integration at the postreceptor level through adaptor protein complexes, influencing cellular dependence on the IGF axis and identifying a patient population with potential to benefit from IGFIR inhibition.