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How does BLV impact the immune system?

Immune System Effects of BLV

The most obvious effect of BLV infection on the immune system is an increase of B cells – a type of lymphocyte – in blood1. B cells are a critical part of the immune system and make antibodies, which protect against infection and are a major component of how vaccines protect against disease. Recent research3,4,14 suggests that BLV-infected dairy cattle have impaired antibody production following vaccination, and so the protection against disease from vaccination is presumably also impaired. Further immunological research is ongoing to determine exactly how BLV interferes with the cow’s immune defenses. Most likely, this immune disruption is responsible for the observation that BLV-infected cattle are culled more quickly than their uninfected herdmates, and also make less milk than their uninfected herdmates5–8. Most of us are aware that HIV/AIDS in people causes an immune suppression, which leaves the infected person vulnerable to a wide range of infections. HIV/AIDS in humans and BLV in cattle are caused by related retroviruses, and they may have a similar immunological impact on their hosts.

For a more detailed discussion of BLV immunology, Meredith Frie has written an excellent review of this topic. The full paper is available by request at: