Immunogenicity of the hookworm Na-ASP-2 vaccine candidate: characterization of humoral and cellular responses after vaccination in the Sprague Dawley rat

Hum Vaccin. 2005 May-Jun;1(3):123-8. doi: 10.4161/hv.1.3.1924. Epub 2005 May 20.


The recombinant larval protein Na-ASP-2 from the human helminth parasite Necator americanus is a lead candidate for a human hookworm vaccine. We have characterized the humoral and cellular immune responses elicited by the Na-ASP-2 formulated with the aluminum-based adjuvant Alhydrogel in the Sprague Dawley rat. We demonstrated that Na-ASP-2 vaccine induced a strong antibody response at all doses tested, as evidenced by high specific IgG1, IgG2a and IgM titers. High IgG antibody titers were maintained up to three months post vaccination and were boosted by an additional vaccine dose. Specific cell proliferation and a Th2 cytokine profile were also observed in peripheral blood of all rats immunized with the formulated vaccine. Host IL-6 levels were also significantly elevated. These data provide evidence that the immune response of the Na-ASP-2 vaccine is robust and durable and therefore suitable for the further clinical development of the Na-ASP-2 vaccine.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adjuvants, Immunologic
  • Aluminum Compounds / pharmacology
  • Animals
  • Antibody Formation / immunology
  • Antigens, Helminth / immunology
  • B-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / immunology
  • Cell Proliferation
  • Cytokines / biosynthesis
  • Dose-Response Relationship, Immunologic
  • Flow Cytometry
  • Hookworm Infections / immunology*
  • Hookworm Infections / prevention & control*
  • Immunity, Cellular / immunology
  • Immunoglobulins / biosynthesis
  • Immunoglobulins / immunology
  • Lymphocyte Count
  • Lymphocytes / drug effects
  • Lymphocytes / immunology
  • Necator americanus / immunology*
  • Rats
  • Rats, Sprague-Dawley
  • Th2 Cells / immunology
  • Vaccines / immunology*


  • Adjuvants, Immunologic
  • Aluminum Compounds
  • Antigens, Helminth
  • Cytokines
  • Immunoglobulins
  • Vaccines