Our results suggest that in some cases, the lower replication capacity of HIV-1 isolates in LTNP1 and ES2 may be the result, rather than the cause, of suppressed evolution: a qualitatively superior HIV-1-specific immune response that limits viral replication will prevent evolution toward greater fitness. … we conclude that the immune system of ES9 is controlling viral replication by at least two different mechanisms: there is a direct inhibition of viral replication by polyfunctional HIV-1-specific CD8+ T cells that proliferate in response to autologous viral peptides, and there is selection for and maintenance of escape mutations that have a negative impact on viral fitness. Vaccines that elicit CD8+ T cells with both properties may be very effective at controlling HIV-1 replication.

Transmission of Human Immunodeficiency Virus Type 1 from a Patient Who Developed AIDS to an Elite Suppressor
Justin R. Bailey, Karen O’Connell, Hung-Chih Yang, Yefei Han, Jie Xu,1 Benjamin Jilek, Thomas M. Williams, Stuart C. Ray, Robert F. Siliciano, and Joel N. Blankson
Journal of Virology, August 2008, p. 7395-7410, Vol. 82, No. 15 doi:10.1128/JVI.00800-08

(My emphasis throughout.)

Further reading:

  1. “Long-term non-progressor”[]
  2. “Elite suppressor”[]