The gut-asso­ci­at­ed lym­phoid tis­sue (GALT) is crit­i­cal for the ini­tial estab­lish­ment and spread of HIV‑1 infec­tion. It is cur­rent­ly thought that type I inter­fer­ons (IFNs), induced dur­ing host innate immune respons­es by var­i­ous pat­tern recog­ni­tion recep­tors, play a key role in coun­ter­act­ing ini­tial viral spread. Type I IFNs are induced in ear­ly HIV‑1 infec­tion, and plas­ma­cy­toid den­drit­ic cells, which pro­duce type I IFNs in large quan­ti­ties, are rapid­ly recruit­ed to mucos­al sites of infec­tion. Type I IFNs like­ly inhib­it HIV‑1 by increas­ing the expres­sion and activ­i­ty of restric­tion fac­tors that direct­ly inhib­it HIV‑1 repli­ca­tion. The exact mech­a­nisms under­ly­ing the anti-HIV activ­i­ty of IFNα are not com­plete­ly under­stood and are very com­plex because IFNα is com­prised of 12 dis­tinct sub­types that pos­sess diverse bio­log­i­cal prop­er­ties. HIV infec­tion of a tar­get cell can be sensed by mul­ti­ple pat­tern recog­ni­tion recep­tors, which leads to the pro­duc­tion of type I IFNs, but if cer­tain sens­ing path­ways are asso­ci­at­ed with spe­cif­ic IFNα sub­type induc­tion is unknown. We estab­lished the Lam­i­na Pro­pria Aggre­gate Cul­ture (LPAC) mod­el to char­ac­ter­ize the induc­tion of spe­cif­ic IFNα sub­types by HIV in mucos­al lym­pho­cytes. To pre­cise­ly quan­ti­fy IFNα sub­type pro­teins in com­plex bio­log­i­cal sam­ples we will set up a unique mass spec­trom­e­try assay. Using a par­al­lel reac­tion mon­i­tor­ing (PRM) mode the new assay should be able to mea­sure pro­tein con­cen­tra­tions of dif­fer­ent IFNα sub­types in patient sam­ples from acute­ly and chron­i­cal­ly HIV-infect­ed patients. More­over a phos­pho pro­teomics stud­ies will be per­formed to analyse the down­stream sig­nal­ing path­ways trig­gered by IFNα sub­types dur­ing HIV infec­tion. Beside the induc­tion of IFNα sub­types we also want to char­ac­ter­ize their indi­vid­ual sig­nal­ing path­ways and we will define the pro­tein regions or sin­gle amino acids that are crit­i­cal for the strong anti-HIV effects of cer­tain IFNα sub­types. This project should pro­vide new insights into how the induc­tion of dif­fer­ent type I IFNs and the acti­va­tion of down­stream sig­nal­ing path­ways may impact mucos­al HIV‑1 infec­tion and patho­gen­e­sis. These results shall help to devel­op strate­gies that aim to use spe­cif­ic IFNα sub­types or IFNα hybrids/​mutants for immunother­a­py against HIV infection.