A rapid method for quantitation of immunofluorescence on human lymphoblastoid cell suspensions.

A quantitative fluoroimmunoassay for antibodies to, and surface antigens of, human lymphoblastoid cells (IM-1) with photon-counting spectrofluorometry is described. IM-1 cell suspensions were reacted with rabbit antiserum to human spleen vesicular membranes, were washed, and then were reacted with an excess amount of fluorochrome-conjugated (fluorescein or rhodamine) goat anti-rabbit immunoglobulin G (IgG). Under appropriate conditions, antibodies to IM-1 cells could be detected with experimental/control fluorescence ratios ranging between 5 and 40. Moreover, detectable levels of antibody-saturated cells approached 5 × 10³ cells per milliliter or a total of 1.7 × 10³ cells per assay. Inhibition of the fluoroimmunoassay was performed with either viable IM-1 cells or IM-1 vesicular membrane preparations and demonstrated a dose-dependent antigen inhibition. Fluorescence of sensitized cells reactive with either fluorescein- or rhodamine-labeled antiglobulins could be quantitatively distinguished in dual-labeled preparations.     

Reproductive ecology of red-chinned lizards (Sceloporus undulatus erythrocheilus) in Southcentral Colorado: comparisons with other populations of a wide-ranging species

Summary We studied the reproductive ecology of a population of Sceloporus undulatus erythrocheilus near Walsenburg, CO during the summers of 1987–1990. Reproductive activity commences soon after emergence in early May and continues until the middle of July. Females mature in their second year following hatching at an age of 20–21 months and a size of 60–63 mm snout-vent length (SVL). Two clutches, averaging10.9 eggs, are produced per year. Larger females produce larger clutches with an increase of one egg per 3 mm SVL. Average SVL of females was 71 mm. Eggs are reasonably large (0.32 g) and relative clutch mass was the largest reported for the species (34% of body mass). A principal component analysis was used to examine relationships among reproductive characters in 12 populations of Sceloporus undulatus. The analysis suggested that patterns of reproduction in this wide-ranging species result from several factors reflecting both adaptive and phylogenetic sources of variation.     

IL-4 bypasses the immune suppressive effect of cyclosporin A during the in vitro induction of murine cytotoxic T lymphocytes

We have analyzed at the clonal level the effect of IL-4 on the immune suppressive action of cyclosporin A (CsA) during the in vitro primary activation of anti-MHC alloantigen-reactive murine CD8+ CTL. Although neither IL-4 nor IL-2 alone were able to overcome the CsA-mediated suppression, the addition of IL-4 in the presence of IL-2 restored in a dose-dependent manner the induction of cytolytic activity. On the other hand, CsA greatly impaired proliferative responses of alloantigen-reactive CD8 T cells, thereby operationally dissecting proliferative responsiveness from acquisition of cytolytic activity during primary activation of alloantigen-reactive CD8+ T cells. The existence of a CsA-resistant induction pathway for Ag-specific CD8+ T cell-mediated cytolytic activity may be of relevance for experimental and clinical organ transplantation.     

Photosynthetic Bradyrhizobia from Aeschynomene spp. Are Specific to Stem-Nodulated Species and Form a Separate 16S Ribosomal DNA Restriction Fragment Length Polymorphism Group

We obtained nine bacterial isolates from root or collar nodules of the non-stem-nodulated Aeschynomene species A. elaphroxylon, A. uniflora, or A. schimperi and 69 root or stem nodule isolates from the stem-nodulated Aeschynomene species A. afraspera, A. ciliata, A. indica, A. nilotica, A. sensitiva, and A. tambacoundensis from various places in Senegal. These isolates, together with 45 previous isolates from various Aeschynomene species, were studied for host-specific nodulation within the genus Aeschynomene, also revisiting cross-inoculation groups described previously by D. Alazard (Appl. Environ. Microbiol. 50:732–734, 1985). The whole collection of Aeschynomene nodule isolates was screened for synthesis of photosynthetic pigments by spectrometry, high-pressure liquid chromatography, and thin-layer chromatography analyses. The presence of puf genes in photosynthetic Aeschynomene isolates was evidenced both by Southern hybridization with a Rhodobacter capsulatus photosynthetic gene probe and by DNA amplification with primers defined from photosynthetic genes. In addition, amplified 16S ribosomal DNA restriction analysis was performed on 45 Aeschynomene isolates, including strain BTAi1, and 19 reference strains from Bradyrhizobium japonicum, Bradyrhizobium elkanii, and other Bradyrhizobium sp. strains of uncertain taxonomic positions. The 16S rRNA gene sequence of the photosynthetic strain ORS278 (LMG 12187) was determined and compared to sequences from databases. Our main conclusion is that photosynthetic Aeschynomene nodule isolates share the ability to nodulate particular stem-nodulated species and form a separate subbranch on the Bradyrhizobium rRNA lineage, distinct from B. japonicum and B. elkanii.