An ex vivo Model of HIV-1 Infection in Human Lymphoid Tissue and Cervico-vaginal Tissue

Abstract

Human tissue explants are a valuable tool to study the interactions between host and infectious agents. They reliably mimic many important aspects of tissue cytoarchitecture and functions and allow us the investigation of the mechanisms of microbial pathogenesis under controlled laboratory conditions. One of the advantages of this system is that, unlike isolated cells, infection of tissue blocks with HIV-1 does not require exogenous stimulation with mitogens or activating factors. Here we describe a protocol to infect with HIV-1 human lymphoid tissue from tonsils and cervico-vaginal tissue and maintain them in culture in a non-polarized setting. These ex vivo infected tissues can be used as fruitful models to study HIV-1 pathogenesis and HIV-1 vaginal transmission, respectively, as well as an efficient platform for testing anti-HIV therapeutic and preventative strategies.

Figure 1. Preparation of tonsillar tissue for culture

(Up) In the received surgical specimens the parts that should be removed are residual fibroid tissue from the capsule surrounding palatine tonsils (white), cauterized tissue (brown-black), bloody/inflamed tissue (red) and any other parts with brown-greenish color. (Middle) Remove unwanted large parts of tissue with a neat cut holding the specimen with forceps. The dotted line delimitates the cutting surface to remove a layer of cauterized tissue. For small parts it may be easier to directly pinch them with forceps to cut them out. (Down) Strips of tissue are dissected into blocks of approximately 8mm³. 9 blocks are transferred on each Gelfoam piece in a 6-well plate.

Figure 2. Preparation of cervico-vaginal tissue for culture

(Up) The endocervix is the part of the uterus lining the lumen of the canal that provides communication between the uterine cavity and that of the vagina. The portion of the cervix that projects into the vagina through the upper anterior vaginal wall is called ectocervix. In the received cervico-vaginal tissue specimens the endocervical mucosa is readily recognized as the part with darker-red color and coated by thick mucus, whereas the ectocervical mucosa has a clearer color. (Middle) The surgical specimen can be cut into smaller pieces to facilitate the removal of the mucosa. Holding the stromal tissue with forceps, separate it from the mucosa cutting the tissue specimens in the longitudinal direction (indicated by the arrows) with respect to the mucosal layer. The dotted line delimitates the cutting surface and should be located 2–3 mm below the epithelial edge of the tissue specimen. (Down) Strips of mucosa are dissected into blocks of approximately 8mm³. After infection 8 blocks are transferred on each Gelfoam piece in a 12-well plate.