Immobilization of microorganisms by adhesion: interplay of electrostatic and nonelectrostatic interactions

The adhesion of three microorganisms (Saccharomyces cerevisiae, Acetobacter aceti, and Moniliella pollinis) to different materials has been studied using various supports (glass, metals, plastics), some of which were treated by an Fe(III) solution. The surface properties of the cells were characterized by the zeta potential and an index of hydrophobicity; characterization of the supports involved surface chemical analysis (XPS) and contact angle measurements. Cell suspensions in pure water at a given pH were left to settle on plates; the latter were then rinsed and examined microscopically, Saccharomyces cerevisiae and A. aceti adhere to metals under certain pH conditions but do not adhere to any of the other materials tested unless it is previously treated by ferric ions; adhesion of these hydrophilic cells is essentially controlled by electrostatic interactions. Moniliella pollinis adhere spontaneously to glass and to polymeric materials, but its attachment is also influenced by cell-cell or cell-support electrostatic repulsions; near the cell isoelectric point, cell flocculation is competing with adhesion to a support.     

Reconstructive surgery for immunosuppressed organ-transplant recipients

Prolonged vascularized organ allograft survival and an improved quality of life are now possible for many transplant recipients. These advances are due largely to greater understanding of the immune response, the development of potent immunosuppressive agents (cyclosporin A), and improved surgical techniques. Thus more of these patients may require surgical procedures related or unrelated to their original operation, and the plastic surgeon, among other specialists, should be aware of the special problems of the immunocompromised transplant recipient who needs to undergo reconstructive surgery. We report our experience with 15 kidney, heart, and liver transplant recipients who required reconstructive surgery for a variety of conditions. The combined team approach by reconstructive and transplant surgeons is described, as well as the perioperative drug protocol and the special problems that immunosuppressed transplant recipients present. We conclude that these patients can successfully undergo major reconstructive procedures as long as the plastic surgeon not only performs technically flawless surgery, but also familiarizes himself or herself with the special problems of the immunosuppressed host, including the ever-present risk of sepsis and delayed and impaired wound healing, the potential for acute Addisonian crisis, and the possibility of multiple complicating comorbid conditions.     

Direct binding of a myasthenia gravis related epitope to MHC class II molecules on living murine antigen-presenting cells.

MHC gene products present antigenic epitopes to the antigen receptor on T cells. Nevertheless, direct binding of such epitopes to MHC class II proteins on normal living antigen-presenting cells (APCs) has not yet been demonstrated. We have previously shown a significant difference in the ability of T cells of myasthenia gravis (MG) patients to proliferate in response to the synthetic peptide p195-212 of the human acetylcholine receptor (AChR) alpha-subunit in comparison to healthy controls. The observed proliferative responses correlated significantly with HLA-DR5. Moreover, lymph node cells of various mouse strains that were primed with the T cell epitope, p195-212, were found to proliferate to different extents. To investigate these observations further, we designed an assay for direct binding of p195-212 to MHC class II proteins on the surface of freshly prepared splenic adherent cells. Binding of a biotinylated p195-212 was monitored using phycoerythrin-avidin by flow cytometry. Fifteen to sixty per cent of the cells were labeled following incubation with the biotinylated peptide. Binding was observed only to splenic adherent cells derived from mouse strains of which T cells were capable of proliferating in response to p195-212. The binding specificity, in terms of epitope structure and its site of interaction on the cells, was shown by its inhibition with an excess of the unlabeled peptide or with the relevant monoclonal anti-I-A antibodies. These results constitute the first direct evidence for the specific binding of a T cell epitope to live APC.     

Pathogenic idiotypes of autoantibodies in autoimmunity: lessons from new experimental models of SLE

Systemic lupus erythematosus (SLE) is considered a classical autoimmune disease that involves many biological systems. Similar to other autoimmune conditions, its etiology is multifactorial entailing genetic, environmental, hormonal, and immunologic factors. In this review we demonstrate that by using a pathogenic idiotype of anti-DNA autoantibodies, it is possible to explain some of the pathogenesis and diversity of clinical and serological manifestations reported by SLE patients. The 16/6 idiotype (Id) is a representative pathogenic idiotype of anti-DNA autoantibodies. The serum titers of 16/6 Id in SLE patients correlate with clinical activity of the disease, and are deposited in afflicted tissues in SLE patients. SLE was experimentally induced in naive mice after immunization with 1 microgram of the Id. The disease is characterized clinically (proteinuria), serologically (e.g., anti-dsDNA, anti-Sm antibodies), and by pathological findings (e.g., deposition of 16/6 Id in the kidneys). The condition can be induced by other human and mouse antibodies carrying the 16/6 Id, as well as by mouse antimonoclonal-16/6 Id and by T cell lines and clones specifically reactive with 16/6 Id. There are strain-dependent differences in susceptibility to the induction of systemic lupus erythematosus (SLE). Induction of SLE is directly correlated with the ability to respond to the 16/6 idiotype (or 16/6 Id)2 by anti-Id antibody production. It is easier to induce the disease in females, and it can be modulated by manipulation of sex hormones. Being able to identify the pathogenic idiotype allowed us to generate T suppressor (Ts) cells specific for the 16/6 Id. Treatment of mice with these T cells abrogated the disease. Our studies point to the importance of pathogenic idiotypes of autoantibodies in autoimmunity, which suggests that SLE may represent a dysregulation of a functional network of idiotypes-anti-idiotypes interactions among autoreactive B cells, T helper cells, and T suppressor cells.     

Progressive immune dysfunction in cats experimentally infected with feline immunodeficiency virus.

Within 6 months of infection with the Petaluma isolate of feline immunodeficiency virus, specific-pathogen-free domestic cats exhibited a decrease in the percentage and number of circulating CD4+ lymphocytes and in the CD4+/CD8+ T-cell ratio, along with a marginally significant depression of pokeweed mitogen-induced lymphocyte proliferation in vitro. There was no loss of responsiveness to concanavalin A during this stage, and the cats were capable of mounting a satisfactory antibody response to a T-dependent, synthetic polypeptide immunogen. The pokeweed mitogen response deficit became clearly demonstrable by 11 to 12 months postinfection. A decline in the lymphocyte proliferative response to concanavalin A and a diminished ability to mount an in vivo antibody response to the T-dependent immunogen evolved by 25 to 44 months postinfection. Virus infection did not affect the ability of cats to mount an antibody response to a T-independent synthetic polypeptide immunogen. These data indicate that feline immunodeficiency virus produces a slowly progressive deterioration of T-cell function but does not affect the ability of B cells to recognize and respond to a T-independent antigenic stimulus.     

Three unique base pair changes in a family with Gaucher disease

Summary Single-stranded cDNA was prepared from RNA obtained from a patient with type 1 Gaucher disease. The cDNA was amplified in vitro and analyzed by sequencing. Three base-pair changes were identified which included a G to C transversion at nucleotide 3119 of the active gene (Asp¹⁴⁰His), an A to C transversion at nucleotide 3170 (Lys¹⁵⁷Gln) and a G to A change at nucleotide 5309 (Glu³²⁶Lys). To study the mode of inheritance of the three different base-pair changes, genomic DNA was prepared from blood or skin fibroblasts of several family members. Genomic glucocerebrosidase DNA sequences were amplified and subjected to hybridization with allele-specific oligonucleotides (ASOs). The hybridization profiles demonstrated that two of the basepair changes originated from the mother and were transmitted to her two affected sons and to a grandchild, while the third base-pair change, originating from the father, was transmitted to his two affected sons, a carrier daughter and a second grandchild. Tests of other patients with Gaucher disease failed to disclose the presence of the three base-changes. This is a unique family with three base-pair changes tightly linked to Gaucher disease.     

Longevity of hibernating queens in Vespa orientalis (Hymenoptera: Vespinae)—Effects of physical and chemical treatments

Young queens of V. orientalis collected from nests in the field at the end of the season, just before the hornets naturally enter hibernation, were evaluated for longevity under varying laboratory conditions. Queens kept under full illumination and heating had a briefer life span than did queens kept under full illumination alone or under complete heating alone. All, however, were shorter lived than control queens kept under the thermal and photoperiodic conditions prevailing at that time in nature. Feeding of theophylline to the queens caused them to emerge from hibernation and succumb to an early death. Feeding of allopurinol to the queens diminished their activities relative to control queens but did not abbreviate their life span compared to the control queens.     

Fine specificity of antibodies to the synthetic polypeptide poly(L-tyrosine, L-glutamic acid)-poly(DL-alanine)--poly(L-lysine) and its ordered analogs as followed by solid-phase radioimmunoassay

The fine specificity of antibodies against (T,G)-A--L and its ordered analogs (T-T-G-G)-A--L and (T-G-T-G)-A--L was studied. Fifty percent of the antibodies against (T,G)-A--L are directed toward the T-T-G-G determinants and 19% against T-G-T-G-like determinants. The rest of the antibody response to (T,G)-A--L is directed against determinants which exist in (T,G)-A--L but are not cross-reactive with either T-T-G-G- or T-G-T-G-like determinants. Although (T-T-G-G)-A--L and (T-G-T-G)-A--L differ only in the sequence of tyrosine and glutamic acid in their side chains, no crossreactivity was observed between antibodies toward the two ordered polypeptide antigens.     

In vitro correction of antigen-induced immune suppression: effects of poly(A) poly(U) and prostaglandin E

Incubation of SJL or DBA/1 mouse spleen cells with poly(lTyr, lGlu)-polylPro—polylLys, (T, G)-Pro—L in vitro reduced the immune response potential of the cells to this immunogen as tested by adoptive transfer into irradiated, syngeneic recipients, followed by immunization with (T, G)-Pro—L in complete Freund's adjuvant. This reduction in immunocompetence was antigen-specific, since incubation with another antigen (rabbit immunoglobulin G) did not result in a suppression of responsiveness of the cells to subsequent in vivo immunization with (T, G)-Pro—L. Incubation of the spleen cell-(T, G)-Pro—L mixture in the presence of either prostaglandin E₁(PGE₁) or polyadenylic-polyuridylic acid (poly(A)·poly (U)) restored the immune response potential to the normal level. Incubation of (T, G)-Pro—L with spleen cells had no effect on cyclic AMP accumulation, whereas incubation of PGE₁ with the cells stimulated cyclic AMP production, irrespective of the presence of antigens. In contrast, the level of cyclic AMP was not affected by poly(A) · poly(U). The difference in cyclic AMP accumulation suggests that PGE₁ and poly(A) · poly(A) modify immune responsiveness by different mechanisms. The above observations were verified both in SJL and DBA/1 mice, which are the respective genetic high and low responders to (T, G) -Pro—L. This implies that the modifications of responsiveness described are not related to the genetic control of immune response to this immunogen.