Abstract #M52
Section: Animal Health (posters)
Session: Animal Health Posters 1
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Exhibit Hall A
Session: Animal Health Posters 1
Format: Poster
Day/Time: Monday 7:30 AM–9:30 AM
Location: Exhibit Hall A
# M52
Impact of a liposome-TLR agonist stimulant on macrophage bactericidal activity against Staphylococcus aureus and on intramammary immune responses.
L. Caixeta*1,2, S. Scheu2, V. Rosso2, W. Wheat2, S. Dow2,3, 1Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN, 2Department of Clinical Sciences, Colorado State University, Fort Collins, CO, 3Laporte Therapeutics, Inc, Fort Collins, CO.
Key Words: mastitis, immune stimulant, bactericidal
Impact of a liposome-TLR agonist stimulant on macrophage bactericidal activity against Staphylococcus aureus and on intramammary immune responses.
L. Caixeta*1,2, S. Scheu2, V. Rosso2, W. Wheat2, S. Dow2,3, 1Department of Veterinary Population Medicine, University of Minnesota, St. Paul, MN, 2Department of Clinical Sciences, Colorado State University, Fort Collins, CO, 3Laporte Therapeutics, Inc, Fort Collins, CO.
Mastitis is a major economic and welfare concern to the dairy industry and it is the most common reason for the use of antibiotics in dairy farms. The development of innovative approaches capable of enhancing udder health will contribute to the judicious use of antibiotics in dairy farms. Thus, the objective of our pilot studies was to investigate the effect of a mucosal immune stimulant (MIS; MucosImmune, Laporte Therapeutics, Fort Collins, CO) on mammary gland immune response. We hypothesized that intramammary (IMM) infusion of MIS would trigger non-specific activation of mammary gland immunity. In Experiment 1, macrophage cultures were generated from monocytes of healthy cattle (n = 3) and incubated with MIS (or PBS) for 24h, then inoculated with a clinical mastitis isolate of S. aureus and intracellular bactericidal activity assessed 4h later. We found that MIS activation of macrophages significantly increased intracellular killing of S. aureus (from 16.7% to 44.2%; P = 0.004), to a level comparable to that generated by IFN-g (P > 0.05). In Experiment 2, lactating dairy cows were randomly allocated to receive IMM administration of either MIS solution (TRT; 1mL MIS and 9mL PBS; n = 4) or 10mL of PBS (UTR; n = 3). Milk samples for TRT and UTR cows were collected at 72h after treatment. Milk samples were incubated with S. aureus and E. coli isolated from mastitis cases for 30 min to measure levels of IgA and IgG that bound to these pathogens. Milk from cows in the TRT group had higher levels of IgA and IgG antibodies against E. coli, but lower levels of antibodies binding to S. aureus (Table). Our preliminary results indicated that MIS is capable of non-specific activation of intra-mammary immunity and increases milk IgA and IgG antibodies against E. coli, but not against S. aureus.
Table 1 (Abstr. M52). Milk immunoglobulin (Ig) A and G against S. aureus and E. coli.
1Geometric mean fluorescence intensity (gMFI).
| Item | TRT | UTR | P-value | |||
| Mean1 | SD | Mean1 | SD | |||
| Anti S. aureus | ||||||
| IgA | 55,346 | 13,833 | 100,847 | 30,595 | <0.01 | |
| IgG | 19,882 | 7,739 | 102,104 | 24,773 | <0.005 | |
| Anti E. coli | ||||||
| IgA | 2,388 | 1,554 | 1,275 | 848 | <0.05 | |
| IgG | 2,871 | 1,742 | 1,888 | 1,456 | <0.05 | |
Key Words: mastitis, immune stimulant, bactericidal
