1. Antibodies and malaria
“always nice to receive a complement”
John Penry
March 24, 2015

2. 1988 Ronald Reagan Seoul Games Die Hard, Rain man, Working girl
Bon Jovi, Guns’n’Roses, George Michael, INXS

3. Veterinary Immunology ‘88
Mostly: B,T cells, monocytes, neutrophils, eosinophils, basophils, mast cells, T helpers
“humoral” “call mediated”
Some: complement, interleukin, interferon
ELISA, W blots, AGID

4. Complement – the history
Discovered in late 1800’s (Jules Bordet, Paul Ehrlich) – “complement”, “alexine”
Opsonisation mediated effect discovered 1930’s (Stanley)
Small proteins, circulating precursors

5. Complement’s roles Links the innate and adaptive arms
Attraction by chemotaxis
Opsonisation
Cell lysis
Agglutination – clustering and binding

6. Complement’s roles
Nature.com

7. Activation pathways Classical Alternative
Lectin (non-self recog.: PAMPS)

8. Cell research, 20, 2010

9. MAC (membrane attack complex)

10. Useful ref: Dunkelberger and Song, Cell Res (2010) 20: 34-50
National Cancer Institute
Useful ref: Dunkelberger and Song, Cell Res (2010)
20: 34-50

11. Our paper
Human antibodies fix complement to inhibit Plasmodium falciparum invasion of erythrocytes and are associated with protection again Malaria
Boyle et al, Immunity 42, 2015

12. Our paper
Human antibodies fix complement to inhibit Plasmodium falciparum invasion of erythrocytes and are associated with protection again Malaria
Antibodies use complement to stop the Malaria organism invading RBCs

13. “The Age” Mar 18

16. Authors and labs

17. Authors and labs

18. Malaria Agent is 5 protozoal spp: Plasmodium Female Anopheles vector
Uncomplicated to severe disease
250M cases/yr worldwide, 1.2M deaths

22. Research thrust
“a lack of established immune correlates of protection severely hampers the evaluation and prioritization of vaccines” “……the role of complement in Ab-mediated protection has not been defined”

23. Toolkit Merozoite invasion assay (FC) Immunoblot
Immuno electron microscope
Immunofluorescence microscopy
ELISA
Flow cytometry
Cohort study

24. IgG (exposed):C dependent inhibitory activity
Aim: to assess the role of C in Ab inhibition of invasion
NS: normal serum – active C
HIS: heat-inactivated serum – inactive C

25. IgG (exposed):C dependent inhibitory activity
MIA
Fig 1
Immunoblot

26. IgG (exposed):C dependent inhibitory activity
IF microscopy

27. IgG (exposed):C dependent inhibitory activity
ELISA

28. Conclusion – part 1
Anti-malaria Abs enhance C deposition on merozoites
Via C1q fixation leading to increased C3b deposition and MAC formation

29. C1q fixation, Ab-C’ inhibition
Aim: what is the relative importance….activated “classical C cascade” vs the “alternative cascade” and: does MAC deposition (lysis) inhibite invasion?

30. C1q fixation, Ab-C’ inhibition
Fig 2
MIA

31. C1q fixation, Ab-C’ inhibition
Flow cytometry

32. Conclusion – part 2
C1q fixation alone was sufficient to mediate substantial Ab-C’ inhibition
M lysis dependent on “classical cascade” – MAC deposition, lysis, not artifact of aglutination
rapid

33. Ab-C’ inhibition predominant
Aim: what is the importance of Ab-C’ inhibition in naturally acquired immunity

34. Ab-C’ inhibition predominant
Fig 3

35. Ab-C’ correlation to cytophilic Mz Ab

36. C1q fixation..correlates..Ab-C’ inhibition
Immunoblot

37. Conclusion – part 3
The majority of human Ab require C factors to inhibit Mz invasion
Ab-C’ is the predominant mechanism – acquired in naturally exposed people
Ab mediated C1q deposition on Mz correlated with Ab-C’ activity

38. Ab-C associated with Mal. protection
Aim: gather epidemiologic evidence of the importance of Ab-C’ in acquired immunity to Malaria
Longitudinal, cohort study
Ab for C1q fixation
Surveillance for parasitemia, clin. Malaria

39. Ab-C associated with Mal. protection
Fig 4

40. Ab-C associated with Mal. protection

41. Ab-C associated with Mal. protection

42. Conclusion –part 4
Increase in Ab dependent C1q deposition seen ….increasing age and in parasitemic children
Consistent with expected acquisition of immunity
High C1q deposition associated with clinical disease protection

43. MSP1/MSP2 targets of Ab-C’
Aim: identify the Mz antigen targets of Ab-C’ inhibition

44. MSP1/MSP2 targets of Ab-C’
Fig 5

45. MSP1/MSP2 targets of Ab-C’

46. Conclusion – part 5
Ab to MSP1 and MSP2 inhibited invasion in the presence of NS, not HIS
Similar for human purified anti MSP2
MSP Ab induced by vacc. able to inhibit invasion via Ab-C’

47. Final words
Ab-C’ inhibition is a prominent mechanism targeting the Mz – naturally acquired immun.
Human anti-Mal Ab have evolved to recruit C for functional activity
An-C’ inhibition can be mediated by Ab through vaccination

48. Cell research, 20, 2010

50. Sir Frank Macfarlane Burnet