Controlled Human Malaria Infection: Strength of a human challenge model. Robert Sauerwein

Transcription

1 Controlled Human Malaria Infection: Strength of a human challenge model Robert Sauerwein )

2 Plasmodium life cycle in human host Clinical symptoms & Pathology 2

3 Controlled Human Malaria Infection (CHMI) Liver stage Blood stage Infective mosquito bite Microscopy positive treatment End of study R. Sauerwein et al. Nat Rev Immunol 2011

4 Parasitaemia after CHMI RTQ-PCR N=48 Parasitemia in 100% of the volunteers Microscopy: Thick smear positive day 7-12 Treatment Microscopy N=48 RTQ-PCR: Cyclic growth of parasites Treatment

5 Parasitaemia after CHMI RTQ-PCR N=48 Parasitemia in 100% of the volunteers Microscopy: Thick smear positive day 7-12 (sensitivity 4000 par/ml) Treatment Microscopy N=48 RTQ-PCR: Cyclic growth of parasites (sensitivity 20 par/ml) Treatment Hermsen C et al. MBP: 2001

6 Parasitaemia by qpcr after bites of 5 infected mosquitoes in 7 CHMI trials in a total of 64 volunteers. + microscopy for parasites post- infection Sauerwein R et al, unpublished

7 Controlled Human Malaria infection (CHMI) Thick smear (4000Pf/ml)) bites of 5 Pf NF54 infected mosquitoes qpcr (20 Pf/ml) Treatment at thick-smear positive Liver-stage blood-stage Data from 48 volunteers in 7 CHMI trials Roestenberg et al., JID, 2012 Sauerwein R et al, Nat Rev Immunol 2011

8 1 + # Pf / ml Hermsen C et al AMJTMH 2004 Statistical model Fitting the data into THE MODEL Days after infection

9 Estimated parasitological parameter values # Hepatocytes infected: 207 (29-560) Asexual cycle 43.7 hrs ( ) rings 28.3 hrs mature trophs 15.4 hrs Multiplication factor : 7.50 ( ) Pre-patent period : MPS 8.8 days ( ) PCR 6.8 days ( ) Hermsen C et al AMJTMH 2004:71:196

10 1 + # Pf / ml 1 + # Pf / ml Simulated kinetics of parasitemia for different vaccine efficacies (a) Pre-erythrocytic vaccine Liver-stage vaccine 0 % 60% 95% 99% Days after infection (b) A-sexual stage vaccine Bloodstage vaccine 0 % 30% 60% 90% Hermsen C et al AMJTMH 2004:71: Days after infection

11 Harmonization of Design and Conduct of CHMI by Mosquito bite CHMI Mosquito Centers in the world: 1. USMMVP, US 2. Sanaria/ NIH/ University of Maryland, US 3. Seattle Biomedical Research Institute, US 4. Oxford University, UK 5. Radboud University Medical Centre,NL Input from USAID, US FDA, NIAID, PATH MVI, EC and EVI. Input from WHO committees Meetings: Bethesda, MD, USA in March 2009; Arusha, Tanzania March 2010 ; Washington, DC in June 2010 (WHO); Amsterdam, June 2011 (EMVDA)

12 PfSPZChallenge: aseptic cryopreserved sporozoites (Sanaria)

13 PfSPZ challenge Advantage: Easy access for global application in appropriate clinical settings. RadboudUMC, NL, Oxford University, UK, Tuebingen University, Germ. CRESIB, Spain, NIH, US. U. Maryland, US, IHC, Tanzania, KEMRI, Kenya,MRTC, Mali, etc : However: fold less potent compared to Pf-infected mosquitoes bites: Viability/potency Administration (route, device, volume) 13

14 In vivo imaging of Pb GFP-Luc con parasites Intravenous versus intradermal injection of sporozoites i.v injection 44 hrs post infection i.d injection Ploemen I. et al: Vaccine 2103

15 Administration of aseptic cryopreserved sporozoites (Sanaria) Direct intravenous inoculation Bypass the skin 3200 Spz (30-60 mosquitoes) 5-10x more potent than ID or IM Bypass of immune interference against spz in the skin

16 Administration of Pf-infected red blood cells intravenously Centres: QIMR, Austr. Oxford University, UK RadboudUMC, NL Cheng AMJTMH 1997; Pombo Lancet 2002 Sanderson AMJTMH 2008, Bijker PNAS 2013

17 Parasites/ml Parasite growth after blood stage infection 10,000,000 PCR determined parasite growth curves 1,000, ,000 10,000 1, Subject 1 Subject 2 Subject 3 Subject 4 Subject Days after inoculation Sanderson et al. AJTMH 2008; 878

18 Blood stage challenge 18 Advantage: Measurement of 4-5 asexual multiplication cycles (compared to 2-3 cycles after mosquito challenge) However: Inoculum (1800 irbc) is unphysiologically low: 10-20x lower than irbc from 1 infective spz Is missing sporo/pre-erythrocytic and cross stages antigens blood stage and sporo/liver stages: LSA3, AMA1, MSP1 Potential induction of immune responses by very low parasitemia trivial?

19 CHMI model: Infection but what about protection? The hunt for Correlate of Protection

20 RTS/S Sub-unit vaccine Interim Results Efficacy Phase IIb/III trial Protection: RTS/S: P. falciparum CSP fused to HBsAg/AS01E 30-50% NEJM :1863; NEJM ; NEJM :1111 Thera et al NEJM 2011;365: Efficacy CHMI parallels Phase IIb/III outcome 20

21 Limited success of these subunit vaccines Poor immunogenicity of individual antigens, Adjuvants; Viral platforms; Prime boost strategies Antigenic diversity of the selected target proteins Genetic diversity coverage Insufficient breadth and coverage of the induced immune response based on mostly single antigens. Antigen Mix/ Match or Attenuated whole parasite

22 Chemo-Prophylaxis and Sporozoites (CPS) Immunization Chloroquine

23 Chloroquine Prophylaxis and Sporozoites (CPS) Immunization CPS Immunization Parasitemia post Challenge qpcr Chloroquine prophylaxis (3 months) 3 x PfSpz infected mosquito-bites 5 PfSpz infected mosquito-bites Roestenberg & McCall et al., NEJM, 2009 Roestenberg et al., Lancet, 2011

24 Protection after CPS-immunization CPS-immunization induces 100% homologous protection. Roestenberg & McCall et al., NEJM, 2009

25 CPS-induced protection is immunization dose-dependent 8/9 19/20 3/5 5/10 Roestenberg & McCall et al., NEJM, 2009 Bijker & Bastiaens et al., PNAS, 2013 Bijker & Teirlinck et al., JID 2014

26 Dissect CPS-induced immune signature 1. Which immune responses are induced by CPS-immunization? 2. Can any of these immune responses correlate with sterile protection from re-infection?

27 Antigen targets of CPS-induced antibodies Comparing CPS Antibody profile with semi-immune Kenyan sera LSA1 MSP2 MSP10 MSP1 CSP MSP (H101) MSP11 LSA3 CPS Immune Reactive 84 Antigens Pre-erythrocytic antigens Reactive in Both 90 Antigens Cross-stage antigens Semi-Immune Reactive 238 Antigens Blood stage antigens Felgner Ph et al Sci Rep 2013

28 Immune Correlate of Protection Chemo-Prophylaxis and Sporozoites (CPS) Analysis of cellular immune responses Antibodies CD4 T cells: IFNγ +/- IL-2 CD8 T cells: IFNγ Cytotoxicity CD107a: degranulation marker Granulysin / Granzyme B: cytotoxic molecules

29 Cytotoxic immune responses in vitro after CPS immunization (C-1). Bijker E et al. JID 2014

30 The RUMC Clinical Malaria Program after >300 CHMI Controlled human Malaria Infections (CHMI): Major upgrade by introduction of molecular detection of parasites by qpcr and development of statistical model Chemo-Prophylaxis and Sporozoite (CPS) immunization : Simple and novel immunization regime inducing long lasting sterile protection with 95% efficacy Better than Nature immunzation protocol challenges dogma s on naturally acquired malaria immunitity Biomarker for protection: First steps in delineation of protective immune signatures Identification of (new) target antigens for protection by system immunological approach

31 Many modalities of Controlled Human Malaria Infections and thus a Fit-for-Purpose Model Pagina 31

32 CCMS-the Netherlands: RUMC /LUMC/EMC Malaria Vaccine Team Clinical team Else Bijker Guido Bastiaens Matthew McCall Meta Roestenberg Jorien Wiersma Linda Wammes Remko Schats Quirijn de Mast Andre van der Ven Leo Visser Perry van Genderen Diagnostic team Rob Hermsen Theo Arens Karina Teelen Lisette van Lieshout Jaco Verweij Jaap van Hellemond Immunology team Anne Teirlinck Wiebke Nahrendorf Marije Behet Anja Scholzen Parasite team Marga vd Vegte-Bolmer Rianne Siebelink-Stoter Wouter Graumans Mosquito team Geert-Jan van Gemert Laura Pelser-Posthumus Astrid Pouwelsen Jacqueline Kuhnen Jolanda Klaassen GAP team Ben van Schaijk Martijn Vos Ivo Ploemen Takechi Annoura Shahid Khan Chris Janse bbb Collaborators Sanaria SL Hoffman STPH Basel/ Bagamoyo S. Shekalaghi C Daubenberger INSERM Dominique Mazier J-F. Franetich UC Irvine: Ph. Felgner CEVAC Ghent L Foquet G Leroux-Rouls