Immunity in humans; long term immunity from plasma cells (Introduction)

by David Turell , Tuesday, February 21, 2017, 21:45 (2621 days ago) @ David Turell

Plasma cells are specialized B cells which produce ling term immunity. It turns out they are supported by specialized T cells. If that support is withdrawn, they disappear:

https://medicalxpress.com/news/2017-02-cells-long-lived-antibody-producing.html

"Using a specialized type of microscope that captures the movement and interaction of cells in living organisms, the scientists observed that, in the bone marrow, immune cells called regulatory T cells closely interact with plasma cells and support them. When the T cells aren't there, plasma cells vanish.

"'This interaction was completely unanticipated," said senior author Christopher A. Hunter, Mindy Halikman Heyer Distinguished Professor of Pathobiology and chair of the Department of Pathobiology at Penn Vet. "If we can understand what controls these long-lived plasma cells, then maybe we can augment that interaction, making more plasma cells to, for example, enhance vaccine efficiency.

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"The research team had noticed that regulatory T cells, which Hunter calls "the health and safety inspectors" of the immune system because they keep immune responses at the appropriate level, were located in a similar region of the bone marrow as the plasma cells, next to the blood vessels. And, when mice were exposed to an infection, these "T regs" declined precipitously, just as the plasma cells had.

"Together, these observations called to mind an earlier finding by another group of scientists that showed that T regs play a key role in protecting the bone marrow from inflammation. In other words, it suggested that T regs make the bone marrow an immune-privileged site, shielding its vital components from the potentially damaging effects of infection or immune response.

"Curious whether these T regs interacted with plasma cells, the researchers examined both cell types in mice that have T regs labeled with a green fluorescent marker and plasma cells labeled with a yellow one. They found that T regs appeared to be closely interacting with plasma cells for extended periods of time.

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"Further studies found that both of these cell types also interact with dendritic cells, which are thought to promote plasma-cell survival. The researchers also demonstrated that T regs were necessary to maintain plasma cells, showing that enhancing T reg survival in mice during infection increased plasma-cell numbers and that experimentally depleting T regs led to reductions in plasma cells.

"The work gives insight into how the body is able to sustain plasma cells for so long, ensuring that they will jump into action even years after a vaccine was administered or an earlier infection was conquered."

Comment: Since infection must be combated, it must be that life has had immune mechanisms from the beginning of life or life might not have survived. This complex cellular arrangement may well have been designed. Hard to argue it wasn't.