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.

Abstract

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.

• Authors: Sachin Gupta, James M Termini, Francesca N Raffa, Cindi-Ann Williams, Richard S Kornbluth, Geoffrey W Stone
• Journal: Journal of virology (J Virol) Vol. 88 Issue 3 Pg. 1492-501 (Feb 2014) ISSN: 1098-5514 [Electronic] United States
• PMID: 24227853 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• AIDS Vaccines
• Antigens, Viral
• Gene Products, gag
• Recombinant Fusion Proteins
• gag Gene Products, Human Immunodeficiency Virus
• CD40 Ligand

Topics

• AIDS Vaccines (administration & dosage, genetics, immunology)
• Animals
• Antigens, Viral (administration & dosage, genetics, immunology)
• CD40 Ligand (administration & dosage, chemistry, genetics, immunology)
• CD8-Positive T-Lymphocytes (immunology, virology)
• Female
• Gene Products, gag (genetics, immunology)
• HIV Infections (immunology, prevention & control, virology)
• HIV-1 (genetics, immunology)
• Humans
• Mice
• Mice, Inbred C57BL
• Recombinant Fusion Proteins (administration & dosage, genetics, immunology)
• Vaccination
• Vaccinia (genetics, immunology)
• Vaccinia virus (genetics, immunology)
• gag Gene Products, Human Immunodeficiency Virus (administration & dosage, genetics, immunology)