Researchers Find That Human Immunodeficiency Virus Spreads Through Direct Cell-To-Cell Contact

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We all along knew that one can contract HIV (Human Immunodeficiency Virus) by coming into contact with certain bodily fluids like blood, semen, breast milk, vaginal fluids, and rectal fluids.

HIV transmission occurs when these fluids get into the bloodstream of an HIV-negative person through a mucous membrane found in mouth, vagina, rectum, or tip of the penis or through open cuts or sores.

A team of scientists from Heidelberg University used innovative cell culture systems, quantitative image analysis, and computer simulations to explore how HIV spreads in three-dimensional tissue-like environments ^[1] . The results reveal that the tissue structure forces the virus to spread through direct cell-to-cell contact.

"Studies on HIV replication in the lab are mostly conducted in simple cell culture experiments in plastic dishes that do not reflect the complex architecture and heterogeneity of tissue", explains study director Prof. Dr Oliver Fackler of the Center for Integrative Infectious Disease Research (CIID) at Heidelberg University.

The researchers revealed that the CD4 T helper cells, the preferred cell type infected by HIV, are increasingly motile in their physiological environment. They used a novel cell culture system, in which a three-dimensional scaffold was generated with the help of collagen. This helped in maintaining the movement of the cells and monitoring primary CD4 T cells infected with HIV-1 in a tissue-like environment over the course of several weeks.

Based on this approach, the researchers measured a number of factors that characterise virus replication, cell motility, and the loss of CD4 T helper cells. Dr Andrea Imle, who worked on the project during her PhD at the CIID says that, "This yielded a very complex set of data that was impossible to interpret without the help from scientists of other disciplines."

While analysing the data, the researchers were able to characterise the complex behaviour of cells and viruses and simulate it on the computer. This created a possibility to make important predictions on the key processes that determine HIV-1 spread in these 3D cultures, which were confirmed by subsequent experimentation.

Dr Frederik Graw of the BioQuant Centre of Heidelberg University explains that, "Our models allowed us to integrate short single-cell microscopy films with long-term cell population measurements and thereby to estimate the minimal time required for cell-to-cell contacts to transmit infection."

The researchers hope that these study findings will lead to new therapeutic approaches in the treatment of HIV.

Disclaimer: The information provided in this article is for general informational and educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or a qualified healthcare provider with any questions you may have regarding a medical condition.