The researchers followed the cases of male twins who were infected shortly after their 1983 births in Los Angeles by blood transfusions administered from the same donor at the same time. Infected with the same strain of the virus, the twins continue to live in the Los Angeles area and grew up exposed to the same environmental forces.

Yet their T-cell receptors (TCR) reacted differently in each twin, showing that the body’s defence response was random—and unpredictable. “These boys are as similar as two humans can be, yet we see differences in how they fight the virus,” said Dr. Paul Krogstad, professor of paediatrics and pharmacology. “That’s one more thing that makes it difficult to develop a vaccine for everyone.”

The twins’ targeting of the HIV was remarkably similar 17 years after infection yet their overall TCR characteristics were highly divergent. The finding, demonstrates that the interaction between their immune systems and the virus was random and unpredictable—indicating that a “one size fits all” vaccine may not be possible.

“If the goal is to develop a vaccine, our findings suggest this may not be so straightforward,” said Dr. Otto Yang, associate professor of infectious diseases at the David Geffen School of Medicine at UCLA, and the study’s lead researcher.

According to the UCLA researchers, the results of this study have broader implications, and could apply to other viruses such as cytomegalovirus (CMV), a herpes virus that causes opportunistic infections in immunosuppressed individuals, and hepatitis C, the latter being similar to HIV in both its changeable and chronic nature.; Source: University of California, Los Angeles (UCLA), Health Sciences