Receptors for opsonins, such as complement component C3b (CR1) and immunoglobulins, Fc receptors, interact with adhesion glycoproteins in mediating immune functions. Defects in expression of the adhesion glycoproteins CD11/CD18 results in severely hampered in vitro and in vivo adherence-related functions of leukocytes. Little is known regarding the effect of leukocyte adhesion deficiency (LAD) on ligand binding and receptor expression. We investigated the binding and expression of CR1 and Fc receptors by bovine neutrophils isolated from dairy calves suffering from LAD, compared with clinically normal (hereafter referred to as normal) age-matched calves. Neutrophils were also assayed for endogenously bound IgG and IgM and for exogenous binding of C3b, IgG1, IgG2, IgM, and aggregated IgG (aIgG), using flow cytometry. Luminol-enhanced chemiluminescence (CL) production in response to IgG2 opsonized zymosan was studied, and specific inhibition of CL was used to determine the specificity of IgG2 binding. Activation of protein kinase C with phorbol myristate acetate was used to determine the effect of cellular activation on expression of CR1. A greater percentage of neutrophils from normal calves bound C3b than did neutrophils from LAD-affected calves. Receptor expression was similar. Activation with phorbol myristate acetate resulted in increased expression of CR1 on neutrophils from normal and LAD-affected calves, but expression was almost twofold greater on neutrophils from normal calves. There was no difference between LAD-affected and normal calves in percentage of neutrophils that bound endogenous IgG and IgM. A greater percentage of neutrophils from normal calves bound exogenous IgM than did neutrophils from LAD-affected calves. Receptor expression for aIgG was greater on neutrophils from LAD-affected calves than on those from normal calves.

Staphylococcal antigens and immune complexes (IC) prepared from antigen and hyperimmune canine serum were tested for their effects on certain functions of mononuclear (MN) and polymorphonuclear (PMN) leukocytes (cells) obtained from healthy dogs. The effect on MN cells was studied by determining the ability of antigen or IC to augment or inhibit mitogenesis induced by phytohemagglutinin (PHA). The effect of antigen or IC on PHA cells was studied by measurement of H2O2 production as an indicator of respiratory burst. Neither the antigen nor the IC, when cultured with MN cells, was mitogenic. Coincubation of antigen or IC with MN cells and PHA resulted in a concentration-dependent decrease in mitogenesis. The decreased mitogenesis could not be overcome by addition of excess PHA, and may in part have been related to toxic effects of the antigen or IC on MN cells. When MN cells were instead preincubated with antigen or IC, then washed and stimulated with PHA, there was still a concentration-dependent inhibition of mitogenesis, although toxicity to the cells was not observed. Low concentrations of staphylococcal antigen or IC stimulated slight H2O2 production by PHA cells. When PHA cells were coincubated with IC and another stimulus (opsonized zymosan or phorbol myristate acetate), IC appeared to augment phorbol myristate acetate-, but not zymosan-induced stimulation. These results suggest that staphylococcal antigens, either alone or complexed with antibody, have the ability to stimulate PMN cells and inhibit MN cell function. Such actions may have a role in the pathogenesis of recurrent staphylococcal infection in canine patients.

Polymorphonuclear neutrophils (PMN) from 4 cows were preincubated (30 minutes, 37 C) in either actinomycin D (100 micrograms/ml) or puromycin (10 micrograms/ml), inhibitors of mRNA transcription and protein translation, or in medium 199. The PMN were incubated for a further 4.5 hours in medium containing 100 U of recombinant bovine interferon-gamma (rboIfn-gamma). The PMN were then incubated with bovine IgG1, IgG2, IgM, or aggregated IgG (aIgG; 4 C, 12 hours) for flow cytometric analysis, using fluoresceinated isotype-specific antibody. The percentage of PMN binding the ligand and the logarithmic mean fluorescent channel (LMFC), an indicator of the amount of receptor (R) expression, were recorded. Competitive inhibition of ligand binding was measured by incubating PMN with fluoresceinated IgG2 in the presence or absence of 100-fold excess of IgG1, IgG2, and aIgG. Activation with rboIfn-gamma induced a 4.5-fold increase in binding of IgG1 and a fivefold increase in LMFC for IgG2. These increases were inhibited by actinomycin D and puromycin. Percentage of PMN binding aIgG decreased after activation by rboIfn-gamma. Interferon-gamma treatment did not affect binding or LMFC of IgM. However, binding of IgM was reduced by treatment with actinomycin D. Binding of fluoresceinated IgG2 was inhibited by unlabeled IgG1, IgG2, and aIgG. Results indicate that bovine PMN Fc receptors (FcR) for IgG1 and IgG2 were rboIfn-gamma inducible, that induction required de novo transcription and translation, that a heterogeneous population of FcR exist on bovine PMN, and that IgG1 and IgG2 share a common FcR. Further, bovine PMN are capable of gene activation and are responsive to changes in their environment, thus being amenable to modulation for effective pathogen destruction.

Four intrauterine treatment strategies were evaluated for effectiveness in mares that were confirmed to be susceptible to chronic uterine infection. Pretreatment samples were obtained at detection of estrus, and a genital strain of Streptococcus zooepidemicus was infused into the uterus when a preovulatory (> 35 mm) follicle was detected. At 12 hours after inoculation, mares were assigned to 1 of 4 selected treatment groups: autologous plasma, 100 ml (n = 5); potassium penicillin, 5 million U in 100 ml of phosphate-buffered saline solution (PBSS; n = 5); 10 mg of prostaglandin F2alpha in 100 ml of PBSS (n = 5); and large-volume lavage with normal saline solution (1,000 ml increments). A fifth group, treated with vehicle alone (100 ml of PBSS), served as a negative control (n = 7). All treatments were administered into the uterus. To assess the effectiveness of the treatment, samples for culture and cytologic examination were collected at 96 hours after bacterial inoculation. An effect of treatment was observed on the number of uterine neutrophils (P = 0.02) and growth of S zooepidemicus (P < 0.01). Intrauterine treatment with potassium penicillin, prostaglandin F2alpha, and large-volume uterine lavage significantly reduced the growth of S zooepidemicus (P < 0.01) as well as the number of neutrophils (P < 0.02). Autologous plasma reduced the number of neutrophils (P < 0.05), but not growth of S zooepidemicus. There was significant correlation between the number of uterine neutrophils and growth of S zooepidemicus for each treatment group (r = 0.57; P < 0.05).

Serum C-reactive protein (CRP) concentration was measured, using an automated immunoturbidimetric assay, in 44 clinically normal dogs and 67 dogs with band neutrophil count greater than or equal to 10(9) cells/L, and values were found to be significantly (P less than or equal to 0.05) different. Correlation of serum CRP concentration and band neutrophil count in the 67 dogs with greater than or equal to 10(9) band neutrophils/L resulted in a statistically significant P less than or equal to 0.05), but low correlation coefficient of 0.34. Serum CRP concentration and CBC values were determined for 6 clinically normal dogs undergoing anesthesia (controls) and 6 clinically normal dogs undergoing anesthesia and ovariohysterectomy. Significant alterations in CBC results and serum CRP concentration, compared with baseline values, were lacking in dogs of the control group. Serum CRP concentration was significantly (P less than or equal to 0.05) increased above baseline values in dogs undergoing surgery and was significantly (P less than or equal to 0.05) increased, compared with values in control dogs by 12 hours after surgery. In dogs undergoing surgery, serum CRP concentration was also significantly (P less than or equal to 0.05) different from values in control dogs at 28 and 36 hours, but not at the 76- and 124-hour sample collection times. Alterations in CBC values compatible with possible or convincing inflammation were detected in 83% of the dogs undergoing surgery at the 8- and 12-hour postsurgery sample collection times, 100% of dogs at 16, 22, 28, and 36 hours after surgery, 83% of dogs at 52 and 76 hours after surgery, 67% of dogs at 100 hours after surgery, and 0% of dogs at 124 hours after surgery It was concluded that significant increases in CRP, concentration in dogs with surgical trauma were not detected earlier than CBC alterations compatible with possible or convincing inflammation.

Corynebacterium pseudotuberculosis phospholipase D (PLD) significantly affected viability of ovine neutrophils after 24 hours' exposure, This effect was more marked in cells that ingested PLD emulsified in oil. Treatment of neutrophils with PLD significantly (P < 0.05) reduced the ability of these cells to migrate toward activated sheep serum. The PLD was not chemotactic, but it activated normal sheep serum, producing factors that were chemotactic for neutrophils.

Canine granulocytic ehrlichiosis was diagnosed in 37 dogs by finding ehrlichial morulae in 0.1 to 26.2% of their blood neutrophils and eosinophils. All 37 dogs had clinical signs of arthritis or muscular stiffness. Titer to Ehrlichia canis was determined in sera from 31 of the 37 dogs; 25 dogs had titer ranging from 1:20 to 1:5,120. In the other 6 dogs, titer to E canis was < 1:10. The most common hematologic abnormality in these dogs, other than rickettsiemia, was thrombocytopenia. Granulocytes infected with ehrlichial organisms were not found in another 10 dogs that had clinical signs of arthritis or muscular stiffness. Of these 10 dogs, 3 had titer to E canis ranging from 1:40 to 1:320. Titer in the other 7 dogs was < 1:10. Ehrlichial morulae were not found in the granulocytes of 18 healthy dogs. Of these 18 dogs, 9 had titer to E canis ranging from 1:20 to 1:5,120. Titer in the other 9 dogs was < 1:10. Titer to Borrelia burgdorferi was determined in dogs with granulocytic ehrlichiosis, arthritic dogs without detected rickettsiemia, and in healthy dogs. Low titer determined by 2 laboratories was considered to be nonspecific reaction in all 3 groups of dogs and, thus, did not indicate that the arthritic disorders were attributable to canine borreliosis.

Sixty-three drugs, belonging to 10 chemical classes, were tested in vitro to determine effects on phagocytosis of 32P-labeled Staphylococcus aureus by neutrophils isolated from milk. Within each class, the number of antibiotics tested were: nonsteroidal anti-inflammatory drugs (NSAID; 8), peptolids (2), aminoglycosides (8), tetracyclines and fusidic acid (4), beta-lactam antibiotics (25), secretolytic agents (2), macrolides (5), polypeptides (2), and antibacterial quinolones (8). Percentage of phagocytosis was determined after incubating (2 hours at 37 C) 12.5 X 10(6) viable neutrophils, 200 X 10(6) 32P-labeled S aureus with antibiotics and 5% skimmed milk. Concentrations of antibiotics tested were 1,000, 500, and 10 microgram/ml of incubation media. When compared with nonantibiotic controls at the highest drug concentration, the NSAID acetylsalicylic acid and centrophenoxine increased phagocytosis 23.2 and 8.8%, respectively, and benzydamine, indomethacin, phenylbutazone, ibuprofen, and acetominophen decreased phagocytosis 22.8, 14.2, 9.8, 27.0, and 18.2%, respectively. The peptolids novobiocin and pristinamycin decreased phagocytosis 24.5 and 22.0%, respectively. The aminoglycosides tobramycin, amikacin, and gentamicin decreased phagocytosis 21.1, 15.4, and 19.2%, respectively. For the tetracyclines and fusidic acid, minocycline and doxycycline decreased phagocytosis 39.8 and 54.2%, respectively. The beta-lactam antibiotics carfecillin, cephapirin sodium, and cephacetrile sodium decreased phagocytosis 11.2, 12.8, and 23.8%, respectively. The secretolytic agent, bromhexin, increased phagocytosis 10.8%. These data indicate that the potential for enhanced phagocytosis exists through use of some NSAID, and for depressed phagocytosis through use of aminoglycosides, peptolids, tetracyclines, and beta-lactams, as well as certain other NSAID.

Neutrophils were purified from blood of dexamethasone-treated (0.04 mg/kg of body weight) and untreated calves. Cells were untreated (controls) or cultured in media containing 5 or 10 ng of bovine recombinant granulocyte-macrophage colony-stimulating factor (rbGM-CSF)/ ml for 10 to 12 hours before being tested for various functions. Dexamethasone treatment of calves decreased luminol-dependent chemiluminescence, decreased phagocytosis of Pasteurella multocida and several Staphylococcus spp by various degrees, and decreased antibody-dependent cell-mediated cytotoxocity against bovine herpesvirus-infected cells by 26 to 32%. The percentage phagocytosis of coagulase-positive S aureus and S intermedius was higher than that of coagulase-negative S epidermidis for neutrophils from all calves. Culture of neutrophils with rbGM-CSF significantly increased (P < 0.05) all of the aforementioned functions, compared with control neutrophils; however, rbGM-CSF-induced increases in function tended to be higher in neutrophils from dexamethasone-treated calves than in neutrophils from untreated calves.