AI Summary
During a bout of influenza, B cells take different paths to defend the body. Some become antibody producing cells, while others become lung-resident memory B cells (lung-BRMs) that provide long-term immunity in the lungs. Understanding the mechanism of lung-BRM development is important for improving flu vaccines. A study has shown that interferon-gamma produced by T follicular helper cells is necessary for the differentiation of B cells into lung-BRMs.
During a bout of influenza, B cells interact with other immune cells and then take different paths to defend the body. One path is the B cells that differentiate into antibody producing cells. Another path is the B cells that differentiate into lung-resident memory B cells, or lung-BRMs, that are critical for pulmonary immunity.
Unlike antibody-producing B cells that help fight the current infection, the long-lived, non-circulating lung-BRMs migrate to the lungs from draining lymph nodes. They reside there permanently and lie in wait as the first layer of defense that can quickly react to produce antibodies in a future infection.
Understanding the mechanism that creates these lung-BRMs is important for better flu vaccine development. Seasonal influenza kills 290,000 to 650,000 people each year, according to the World Health Organization. Yet flu vaccines are less effective in the elderly -; the most at-risk population -; compared to younger people. Also, there is need for vaccines that are more effective against later variants of a particular virus.
André Ballesteros-Tato, Ph.D., and colleagues at the University of Alabama at Birmingham have now published a mouse-model study in the journal Immunity showing that interferon-gamma produced by T follicular helper cells, or Tfh cells, after intranasal influenza infection is required to initiate the path of B cell differentiation into lung-BRMs. Ballesteros-Tato is an associate professor in the UAB Department of Medicine Division of Clinical Immunology and Rheumatology
During influenza infection, both Tfh and B cells are present at germinal centers in the lymph