Home > Interesting link, Recent News > New “prime and pull” vaccine model offers new hope against retroviruses

New “prime and pull” vaccine model offers new hope against retroviruses

Excerpt from ScienceTechDaily

New Model for Vaccination Against Genital Herpes

Until now, most efforts to develop a vaccine have focused on the immune system’s antibodies, or T cells, circulating through the body. When T cells encounter foreign invaders such as bacteria or viruses, they learn to recognize them and mount ever-stronger immune responses to fight them. But efforts to harness these circulating T cells have not been effective in organs such as the vagina, intestines, lung airways, and central nervous system, which restrict the entry of these “memory” T cells.

To investigate an alternative approach, the Yale team focused instead on peripheral tissue in the female genital tract, where viral exposure occurs. The challenge was to recruit virus-specific T cells into the vaginal mucosa without triggering a potentially harmful inflammatory response of the immune system.

Working with mice, they explored a two-part vaccine strategy they call “prime and pull.” The “priming” involved conventional vaccination to elicit a system-wide T cell response. The “pulling” involved recruitment of activated T cells directly into the vaginal tissue, via topical application, of chemokines — substances that help mobilize the immune cells.

 

The original study can be found here

A vaccine strategy that protects against genital herpes by establishing local memory T cells by Haina Shin & Akiko Iwasaki

Most successful existing vaccines rely on neutralizing antibodies, which may not require specific anatomical localization of B cells. However, efficacious vaccines that rely on T cells for protection have been difficult to develop, as robust systemic memory T-cell responses do not necessarily correlate with host protection1. In peripheral sites, tissue-resident memory T cells provide superior protection compared to circulating memory T cells2, 3. Here we describe a simple and non-inflammatory vaccine strategy that enables the establishment of a protective memory T-cell pool within peripheral tissue. The female genital tract, which is a portal of entry for sexually transmitted infections, is an immunologically restrictive tissue that prevents entry of activated T cells in the absence of inflammation or infection4. To overcome this obstacle, we developed a vaccine strategy that we term ‘prime and pull’ to establish local tissue-resident memory T cells at a site of potential viral exposure. This approach relies on two steps: conventional parenteral vaccination to elicit systemic T-cell responses (prime), followed by recruitment of activated T cells by means of topical chemokine application to the restrictive genital tract (pull), where such T cells establish a long-term niche and mediate protective immunity. In mice, prime and pull protocol reduces the spread of infectious herpes simplex virus 2 into the sensory neurons and prevents development of clinical disease. These results reveal a promising vaccination strategy against herpes simplex virus 2, and potentially against other sexually transmitted infections such as human immunodeficiency virus.

 

Advertisements
  1. No comments yet.
  1. No trackbacks yet.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: