HIV and T helper cells

Question

As far as I know and could understand from reading about HIV, T helper cell is one of the main reasons to develop AIDS in patients infected with HIV virus, that because the absence of helper T cell suppresses the immune system because no T cell cytokines released to allow other white blood cells to attack or release antigens.

Q1. Did I understand it correctly?

Q2. Now if my understanding is correct, why don't scientists find a way to produce T cell cytokines in the lab? and then inject it to patients with HIV? wouldn't that in theory revive the immune system and perhaps heal them or at least make them live longer?

P.S. My knowledge is close to nothing in this topic, so excuse me if the question itself is wrong :)

Answer 1

Q1: Partially. T cells are important for the immune response through pathways other than cytokine release. Being activated by contact with another immune cell presenting their corresponding antigen, T cells proliferate and themselves activate their compatible B cell counterpart. These then produce antibodies specific to that antigen, the basis of the adaptive immune response (see figure below, from Wikipedia). The important part here is that this mechanism requires cell-to-cell contact, not simply cytokines. Without it, any pathogen for which memory B cells do not exist yet will not produce an adaptive immune response - and will persist if the infection is not cleared by the innate immune response.

Q2: I expect because merely injecting T cell cytokines would not be sufficient in order to replace the essential function of T cells. Aside from that, WYSIWYG's point about the general response is probably also true: the side effects would be horrendous.

Answer 2

1. yes
2. [Purely my guess] :

I think it will be difficult when simultaneously several infections pop up. There is no antigen presentation (as there is no receiver); it will be difficult to manually deliver different kinds of responses by cytokine injection.

Moreover most cytokines are paracrine i.e they act locally; injecting them would cause a systemic response which may be harmful.

Plus, it might be expensive to perform a cytokine therapy. [interferons are used in certain viral infections and what I vaguely remember is that the therapy is expensive]

Answer 3

1. yes you understand how helper T cells work in the body.

2. no. Cytokines are not enough and injecting T cells will just make HIV persist. The only solution to not getting AIDS and having your HIV cured is an HIV vaccine and the people making the vaccines do produce some HIV vaccine.