Toxoplasma gondii: humoral and cellular immune response of BALB/c mice immunized via intranasal route with rTgROP2

Rev Bras Parasitol Vet. 2010 Oct-Dec;19(4):210-6.

Toxoplasma gondii: humoral and cellular immune response of BALB/c mice immunized via intranasal route with rTgROP2

Igarashi M, Zulpo DL, Cunha IA, Barros LD, Pereira VF, Taroda A, Navarro I, Vidotto O, Vidotto MC, Jenkins MC, Garcia JL.

Laboratório de Protozoologia, Departamento de Medicina Veterinária Preventiva, Universidade de Londrina - UEL, CP 6001, CEP 86050-970Londrina - PR, Brazil. jlgarcia@uel.br.

Abstract
TgROP2 is an intracellular protein associated with rhoptries of Toxoplama gondii and an antigen component of a candidate vaccine for toxoplasmosis. The purpose of the present study was to evaluate the efficacy of rTgROP2 to stimulate humoral and cellular immune responses in BALB/c mice via intranasal injection. TgROP2 partial coding sequence was (196-561) amplified by PCR from genomic T. gondii RH strain DNA and cloned into the pTrcHis expression vector. Escherichia coli Rosetta 2 cells transformed with pTrcHis-TgROP2 showed high levels (~1 mg.mL(-1)) of recombinant protein after 4 hours of IPTG induction. Recombinant TgROP2 exhibited an apparent Mr equal to 54 kDa. In order to test immunogenicity of the recombinant protein, 10 BALB/c mice received 10 µg of rROP2 protein + 10 µg of Quil-A via intranasal injection. Doses were administered at days 0, 21, and 42. Three animals were euthanized and used to evaluate cell-ular immune response on day 62. Five (50%) and two (20%) out of ten animals produced IgG (DO mean = 0.307; cut-off = 0.240) and IgA (DO mean = 0.133, cut-off = 0.101), respectively, by ELISA on day 62. The proliferation of splenocytes revealed high stimulation index (SI) when co-cultured with 5, 10 and 15 µg.mL(-1) of rTgROP2. These results indicate that intranasal immunization with recombinant protein ROP2 plus Quil-A can elicit both cellular and humoral immune responses in BALB/c mice.

PMID: 21184696