Pneumonia Vaccine Found to Halt Atherosclerosis

A study has demonstrated that vaccination with pneumococci microbes and the resulting immune response can reduce the extent of atherosclerosis by 21% in laboratory mice used as a model of coronary disease. The results were reported in the May 12, 2003, online issue of Nature Medicine.

Although pneumococcal vaccination is known to build the body's defenses against bacterial pneumonia, this is the first demonstration that a pneumococcal vaccine can also protect the host from a chronic inflammatory disease process such as atherosclerosis. In the study, researchers discovered that a chemical structure called phosphorylcoline on the surface of oxidized low-density lipoprotein (LDL) was identical to a molecular site on S pneumoniae, the major cause of bacterial pneumonia.

In turn, a natural antibody, IgM, reacted with both pneumococcal bacteria and oxidized LDL by binding to that chemical structure. Based on these observations, the researchers tested vaccination with pneumococci in laboratory mice and determined that the resulting immune response arrested the progression of atherosclerosis.

"We've established that IgM antibodies specific for oxidized LDL have a protective role in atherosclerosis,” said co-senior author Joseph Witztum, M.D., professor of medicine at the University of California, San Diego (CA, USA). "This provides insight into the biological role of these immune responses and is an important basis for the development of therapeutic interventions.”




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