2. MAMMARY IMMUNE SYSTEM Lactation Biology Animal Science 337 Leo Timms Iowa State University

3. ANATOMY AND PHYSIOLOGY OF THE UDDER

4. Mammary Defense Mechanisms skin Teat Shape * * heritable Teat * placement

5. * * * heritable

6. The Mammary Gland Streak Canal Keratin epithelial cells, fatty acids & cationic proteins

7. The Mammary Gland Furstenburg’s Rosette Leukocyte Influx to Teat Cistern

11. MAMMARY GLAND IMMUNE SYSTEM Depends on mammary gland status Lactating vs. Dry (involuted) Normal (uninfected) vs. inflamed

12. NORMAL LACTATING GLAND (milk) Cellular: < 100,000 cells/ml (WBC or SCC) MǾ: 60-80% PMN: 10-30% Lymphocytes: ~ 10 % (T and B) (some local Ig synthesis) Humoral: Low levels of Ig, complement, lactoferrin

13. INFECTED LACTATING GLAND (milk) Cellular: > 200,000 cells/ml (WBC or SCC) MǾ: 10 - 40% PMN: 50 - 90% Lymphocytes: ~ 10 % (T and B) (some local Ig synthesis) Humoral: Higher levels of Ig, complement, lactoferrin

14. NORMAL DRY GLAND Cellular: Day in dry period. 50 d dry 1 2+3 10 10-25 25-45 45-50 cells/ml 10 6 >10 6 >10 6 Cell type MǾ PMN PMN/ MǾ Lym/ MǾ MǾ Humoral: Lactoferrin high Complement low Ig: increase through dry period (colostrum) DILUTION? SUSCEPTIBILITY?

20. Natural Teat Sealing

21. ‘Open’ teats observed using the same method in NZ and Canada

22. Results Quarter Closure: Variable between herds

23. Results Hazard Ratio = 0.56 P < 0.01

24. > 20% of heifer teats are open prior to calving!!!

27. #’s or levels don’t tell whole story 1. Poor Ig transport across blood-milk membrane selective: colostrum (specific!) Non specific: leakage (not specific for Ag) Immunize: IM, IP, IMM (local vs. systemic Ig)

28. #’s or levels don’t tell whole story 1. Cells in milk poorer than blood Lack of energy (glucose) Lose 40% of granules crossing membrane Cells phagocytize fat and protein

29. CAN SCC GET TOO LOW?