Table 1.
Comparable immune parameters in wild-type mice (MOR +/+) and mice lacking the μ-opioid receptor (MOR −/−)
| Immune parameters | MOR +/+ | MOR −/− | ||
|---|---|---|---|---|
| Lymphoid organ size | Spleen | Weight, mg/g body weight | 4.1 ± 0.03 (11) | 4.6 ± 0.4 (10) |
| Cells/100 mg spleen (× 107) | 9.7 ± 1.0 (24) | 11.6 ± 1.2 (23) | ||
| Thymus | Weight, mg/body weight | 4.0 ± 0.4 (11) | 4.2 ± 0.4 (11) | |
| Cells/100 mg thymus (× 107) | 19.5 ± 1.7 (17) | 20.5 ± 1.8 (18) | ||
| Cell distribution | Spleen | % B lymphocytes | 45.6 ± 1.8 (15) | 48.2 ± 1.5 (14) |
| % CD4+ T lymphocytes | 27.2 ± 1.9 (10) | 26.1 ± 2.4 (8) | ||
| % CD8+ T lymphocytes | 13.7 ± 1.3 (11) | 9.8 ± 0.6 (10) | ||
| Thymus | % CD4+ lymphocytes | 14.3 ± 4.0 (6) | 14.1 ± 1.4 (6) | |
| % CD8+ lymphocytes | 5.5 ± 2.1 (6) | 4.6 ± 0.5 (6) | ||
| % CD4+CD8+ lymphocytes | 77.9 ± 6.4 (6) | 78.9 ± 2.2 (6) | ||
| Splenocyte responsiveness | NK activity | LU/107 cells | 11.1 ± 1.0 (10) | 14.1 ± 1.5 (10) |
| T lymphocytes | In vitro proliferation (P.I.) | 18.7 ± 1.9 (10) | 17.7 ± 2.9 (10) | |
| B lymphocytes | In vitro proliferation (P.I.) | 11.9 ± 1.1 (10) | 10.0 ± 0.6 (10) | |
| In vitro Ig production, μg/ml | 7.8 ± 0.9 (10) | 9.8 ± 1.6 (10) | ||
| Serum immunoglobulins | Total Ig, mg/ml | 3.4 ± 0.5 (12) | 3.4 ± 0.3 (12) | |
| IgM, mg/ml | 0.24 ± 0.03 (12) | 0.21 ± 0.03 (12) | ||
NK activity was measured by a 51Cr release assay and is expressed as lytic units (LU) per 107 effector cells. In vitro splenic T and B lymphocyte proliferation was assessed after mitogenic stimulation and is presented as proliferation indices (P.I.), calculated as ratios of cpm incorporated in the presence of mitogen to cpm incorporated in the absence of mitogen. Total Ig production by in vitro LPS stimulated splenocytes as well as serum total Ig and IgM levels were determined using ELISA. Results are shown as means ± SEM. Numbers in parentheses represent the number of mice analyzed. Data from both genotypes were compared using the two-tailed Student’s t test. P values were >0.05 for all measured parameters.