Page 124 - Veterinary Immunology, 10th Edition

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FIG. 4.16 The mutation that results in canine C3 deficiency.
Deletion of a cytosine results in a frameshift and premature
termination of transcription of the C3 gene.

Porcine Factor H Deficiency

FH is a critical component of the alternative complement pathway.
It normally inactivates C3b as soon as it is generated and so
prevents excessive complement activation. If an animal fails to
make FH, C3b will be generated in an uncontrolled fashion. FH

deficiency has been identified as an autosomal recessive trait in
Yorkshire pigs. Affected piglets are healthy at birth and develop
normally for a few weeks. However, eventually they fail to thrive,
stop growing, become anemic, and die of renal failure.

On necropsy, there are multiple petechial hemorrhages on the
surface of the kidneys, accompanied by atrophy of the renal
papillae. Mesangial cell proliferation and capillary basement
membrane thickening occur within glomeruli (Fig. 4.17). On

electron microscopy, extensive intramembranous electron-dense
deposits are found in the glomerular basement membranes (Fig.
4.18). This is typical of type II membranoproliferative
glomerulonephritis (Chapter 32). Indirect immunofluorescence tests

demonstrate massive deposits of C3, but no immunoglobulins in
the basement membranes. C3 can be found in the glomeruli before
birth, but mesangial proliferation and intramembranous dense
deposits develop after 5 days of age.

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