1. ! eg. cattle responses to Boophilus tick GROOMING AVOIDANCE PUSTULE
IMMUNITY PARASITES MULTIPLE RESPONSES AGAINST PARASITE
eg. cattle responses to Boophilus tick !
GROOMING
AVOIDANCE
PUSTULE
EOSINOPHILS
ANTIBODY
GRANULOMA

2. • Rhipicephalus sanguineus infected with Babesia canis
IMMUNITY PARASITES REFRACTORINESS / SUSCEPTIBILITY
• Rhipicephalus sanguineus infected with Babesia canis
• Ixodes ricinus infected with Borrelia burgdorferi Ab
grooming wrong receptors phagocytosis
(human is refractory)
(human is partial refractory / susceptible)
spirochaetes in
joint
grooming evasion of antibody evasion of phagocytosis

3. eg. Trypanosoma in blood plasma
IMMUNITY PARSITES ANTIBODY ON EXTRACELLULAR PROTOZOA
eg. Trypanosoma in blood plasma U
surface antigen membrane lysis +
C3b complement
complement mediated
lysis and opsonisation +
phagocytosis Th B

4. Th B stimulatory factors secretory antigen antibody
IMMUNITY PARASITES IMMUNE EXPULSION OF GUT NEMATODES B Th U
secretory
antigen
antibody
nematode inactivation nematode expulsion
stimulation of goblet cells
+ type 1 hypersensitivity
releasing mast cell amines
aid expulsion of inactive
worms
stimulatory factors
gut with goblet cells U U U U U U U

5. Types 1 and 4 are both active against mites, ticks, fleas
IMMUNITY PARASITES CUTANEOUS HYPERSENSITIVITY - TYPE 1
Types 1 and 4 are both active against mites, ticks, fleas
• TYPE 1 produces amines leading to eosinophil
degranulation protein which is toxic to macro-parasites. Y
IgE antibody
antigen
histamine
serotonin
eosinophils basophils neutrophils
sensitised mast cell
degranulates when
exposed to antigen
attraction of granulocytes

6. Types 4 and 1 are both active against mites, ticks, fleas
IMMUNITY PARASITES CUTANEOUS HYPERSENSITIVITY - TYPE 4
Types 4 and 1 are both active against mites, ticks, fleas
• TYPE 4 activates macrophages which stimulate
fibroblasts to produce granuloma and neutrophils
to form intra-epidermal pustules U
T cell
sensitised T lymphocyte
releases lymphokines
macrophage
activation
neutrophils
lymphocytes
antigen
fibroblasts

7. Antibody mediated cytotoxicity against Schistosoma, Fasciola etc
IMMUNITY PARASITES EOSINOPHILS AGAINST HELMINTHS IN TISSUE
Antibody mediated cytotoxicity against Schistosoma,
Fasciola etc
• Secretory / excretory antigens stimulate production of
antibody from B lymphocytes and eosinophil
stimulation promoter from T lymphocytes.
• Antibody opsonises helminth larva, eosinophils
degranulate around it and kill it. B Th
antigen Y Fc
antibody
eosinophil stimulation
degranulation
opsonisation

8. INTRACELLULAR PROTOZOA (eg Leishmania)
IMMUNITY PARASITES MACROPHAGE ACTIVATION AGAINST
INTRACELLULAR PROTOZOA (eg Leishmania)
• Type 4 hypersensitivity: antigen stimulates T
lymphocytes to produce interferon gamma. This activates
infected macrophages to produce NO and H2O2 and
extra lysosomal enzymes, all toxic to Leishmania
APC
T cell
IFNg
activated macrophage kills Leishmania
antigen
Leishmania in
parasitophorous
vesicle within
macrophage

9. INTRACELLULAR PROTOZOA eg Theileria parva
IMMUNITY PARASITES CYTOTOXIC T LYMPHOCYTES AGAINST
INTRACELLULAR PROTOZOA eg Theileria parva
• Antigen is presented to CTL and they proliferate.
• Antigen + MHC receptors on CTL permit specific
binding to infected lymphocytes.
• Bound CTL release toxic granules to kill infected cell.
APC
CTL
antigen released
specific
granule release
T lymphocyte with Theileria schizont T lymphocyte killed

10. VARIATION in Trypanosoma
IMMUNITY PARASITES EVASION OF ANTIBODY BY ANTIGENIC
VARIATION in Trypanosoma
• Trypanosoma antigens stimulate antibody production.
• These antigens can vary in successive generations of
Trypanosoma.
• Each new variant can evade the preceding antibody
response until new antibody is produced. a b c d
Trypanosoma per
mm3 of blood,
variants a - d
Titre of antibody to
Time (each peak takes several weeks)