Temporal dynamics of persistent germinal centers and memory B cell differentiation following respiratory virus infection.

Following infection or immunization, memory B cells (MBCs) and long-lived plasma cells provide humoral immunity that can last for decades. Most principles of MBC biology have been determined with hapten-protein carrier models or fluorescent protein immunizations. Here, we examine the temporal dynamics of the germinal center (GC) B cell and MBC response following mouse influenza A virus infection. We find that antiviral B cell responses within the lung-draining mediastinal lymph node (mLN) and the spleen are distinct in regard to duration, enrichment for antigen-binding cells, and class switching dynamics. While splenic GCs dissolve after 6 weeks post-infection, mLN hemagglutinin-specific (HA+) GCs can persist for 22 weeks. Persistent GCs continuously differentiate MBCs, with "peak" and "late" GCs contributing equal numbers of HA+ MBCs to the long-lived compartment. Our findings highlight critical aspects of persistent GC responses and MBC differentiation following respiratory virus infection with direct implications for developing effective vaccination strategies.

A qualitative study exploring older smokers' attitudes and motivation toward quitting during the COVID-19 pandemic.

Older individuals who smoke are at increased risk of having severe outcomes from COVID-19, due to their long-term smoking and underlying health conditions. In this qualitative study, we explored the impact of COVID-19 on attitudes toward smoking and motivation to quit. Participants (N = 30) were enrolled in a larger ongoing randomized controlled smoking cessation trial conducted in the lung cancer screening setting. From March to May 2020, we assessed quantitative and qualitative responses to participants' overall concern about COVID-19, changes in amount smoked, and motivation to reduce/quit smoking. Responses to the quantitative questions indicated that 64.3% of participants were extremely concerned with COVID-19, 20.7% reported reductions in amount smoked, and 37.9% reported increased motivation to quit. The qualitative responses, which were transcribed and coded using Consensual Qualitative Research guidelines, expanded upon these findings by providing the content of participants' concerns, which included perceived risk of contracting COVID-19, the added stressors caused by COVID-19, and a variable impact on the amount smoked and motivation to quit. Although half of participants expressed extreme concern regarding COVID-19, fewer indicated increased motivation or reduced smoking. Qualitative themes suggested that the initial two months of the pandemic prompted some smokers to reduce or quit, but it exacerbated smoking triggers for others. Understanding how the pandemic continues to affect this vulnerable group will aid in adapting methods to support their efforts to stop smoking and remain abstinent.