Vaccination with a fusion protein that introduces HIV-1 gag antigen into a multitrimer CD40L construct results in enhanced CD8+ T cell responses and protection from viral challenge by vaccinia-gag.
CD40 ligand (CD40L, CD154) is a membrane protein that is important for the activation of dendritic cells (DCs) and DC-induced CD8(+) T cell responses. To be active, CD40L must cluster CD40 receptors on responding cells. To produce a soluble form of CD40L that clusters CD40 receptors necessitates the use of a multitrimer construct. With this in mind, a tripartite fusion protein was made from surfactant protein D (SPD), HIV-1 Gag as a test antigen, and CD40L, where SPD serves as a scaffold for the multitrimer protein complex. This SPD-Gag-CD40L protein activated CD40-bearing cells and bone marrow-derived DCs in vitro. Compared to a plasmid for Gag antigen alone (pGag), DNA vaccination of mice with pSPD-Gag-CD40L induced an increased number of Gag-specific CD8(+) T cells with increased avidity for major histocompatibility complex class I-restricted Gag peptide and improved vaccine-induced protection from challenge by vaccinia-Gag virus. The importance of the multitrimeric nature of the complex was shown using a plasmid lacking the N terminus of SPD that produced a single trimer fusion protein. This plasmid, pTrimer-Gag-CD40L, was only weakly active on CD40-bearing cells and did not elicit strong CD8(+) T cell responses or improve protection from vaccinia-Gag challenge. An adenovirus 5 (Ad5) vaccine incorporating SPD-Gag-CD40L was much stronger than Ad5 expressing Gag alone (Ad5-Gag) and induced complete protection (i.e., sterilizing immunity) from vaccinia-Gag challenge. Overall, these results show the potential of a new vaccine design in which antigen is introduced into a construct that expresses a multitrimer soluble form of CD40L, leading to strongly protective CD8(+) T cell responses.
Department of Microbiology and Immunology, Center for AIDS Research, and the Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, Florida, USA.
Sachin
S
Gupta
James M
JM
Termini
Francesca N
FN
Raffa
Cindi-Ann
CA
Williams
Richard S
RS
Kornbluth
Geoffrey W
GW
Stone
D016915:AIDS Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D000818:Animals; D000956:Antigens, Viral / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D023201:CD40 Ligand / Q000008:administration & dosage / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000821:virology; D005260:Female; D015683:Gene Products, gag / Q000235:genetics / Q000276:immunology*; D015658:HIV Infections / Q000276:immunology / Q000517:prevention & control* / Q000821:virology; D015497:HIV-1 / Q000235:genetics / Q000276:immunology*; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D011993:Recombinant Fusion Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014611:Vaccination; D014615:Vaccinia / Q000235:genetics / Q000276:immunology; D014616:Vaccinia virus / Q000235:genetics / Q000276:immunology; D054301:gag Gene Products, Human Immunodeficiency Virus / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*
D016915:AIDS Vaccines; D000956:Antigens, Viral; D015683:Gene Products, gag; D011993:Recombinant Fusion Proteins; D054301:gag Gene Products, Human Immunodeficiency Virus; D023201:CD40 Ligand