It is possible to safely protect human volunteers immunized with P. vivax irradiated sporozoites from P. vivax challenge with live sporozoites.

Title: Phase 1 and Phase 2a Clinical Trial: Immunization of human volunteers with P. vivax irr-spz. (Short name: Irrad-SPZ) Population 27 healthy adult volunteers, males and non-pregnant females, between 18-45 years of age, who fulfill inclusion/exclusion criteria (described below) as determined by clinical history and serological tests. Approximately 20 parasitized blood-donor volunteers will be required to infected Anopheles mosquitoes which will be used to immunize volunteers with a total of 1000-1500 infected mosquitoes, during 8-10 months. Afterwards challenge to prove protection.

Number of Sites: 2 Study Duration: 2 years. Subject Duration : Step1: 1-2 hours to blood donors; Step 2 and 3: 2 years to immunized volunteers Objectives Primary

• To assess the safety and protective efficacy of P. vivax irradiated sporozoite vaccination.

Secondary

• To determine the immune responses and duration elicited by the P. vivax challenge in human Fy(+) volunteers previously immunized with irr-spz, as compared with non-immunized human volunteers.
• To determine the immune responses and duration elicited by irr-spz immunization scheme in human Fy(+) volunteers; comparing it with the same immunization scheme with non irr-spz in Fy(-) participants, and also with controls exposed to the same mosquito bite scheme as that of immunization but using mosquitoes without parasite infection.
• To study new antigens potentially useful to induce pre-erythrocytic protection against P. vivax malaria infection

Inclusion Criteria:

• • Healthy 18 to 45 years old man or non-pregnant women.

  • To have the capacity to sign an informed consent in a free and voluntary way.
  • Have an acceptable understanding of the clinical trial through the approval of a questionnaire regarding the information given in the consent process.
  • Obligatory use of adequate contra-conceptive method from beginning of recruitment and screening time up to three months after last immunization
  • Do not have chronic or acute diseases. These conditions will be determined by clinical history, physical exam and laboratory tests.
  • To accept not traveling to malaria endemic areas during the clinical trial should
  • To have telephone at home or mobile phone that permit permanent contact for follow up
  • He (she) manifest that is willing to participated during both steps of the clinical trial.

Exclusion Criteria:

• Volunteers with less than 18 old year or more than 45 old years.
• Pregnant and suckling women will be excluded. Pregnancy will be determined both by interview, and by serum B-subunit chorionic gonadotrophin testing.
• History of moderate or severe insect, or food allergies.
• G-6PD deficiency or any Hb genetic defect (for example; sickle cell disease)
• Previous malaria infection demonstrated by think smear, PCR or specific antimalarial antibodies.
• If the subject has previously participated in a malarial vaccine trial.
• Clinical record of allergies to drug or insect bites.
• Symptoms, signs or data from laboratory test that suggests to the physician any systemic disorder like renal, hepatic, cardiovascular, pulmonary, psychiatric disorders or other illnesses that could interfere with results of clinical trial or could compromise the health of the volunteer.
• To have antibodies against hepatitis C, VIH, or hepatitis B superficial antigen and/or hepatitis B core antibodies.
• To have any abnormality in the parameters assessed by blood laboratory tests. Base-line values will be established before initiation of the clinical trial.
• Presence or history of an auto-immune disease such as; Asthma, lupus, rheumatoid arthritis, Graves's disease, Hashimoto tyroiditis, and others.
• History of surgical removal of the spleen (splenectomy).
• Volunteer with medical treatment known to alter the immune system before 3 months to recruitment, such as; cortico-steroids, chemotherapeutic agents, fludarabine, cyclosporine, tacrolimus, mycophenolate mofetil, rapamycine, ATG, alemtuzumab.
• Alcoholism or drug abuse that may interfere with social relationship of individual.