Nasal secretion protein responses in patients with wild-type adenovirus disease

Microfluidic chip for fast bioassays-evaluation of binding parameters

A seven channel polystyrene (PS) microchip has been constructed using a micromilling machine and a high-temperature assembling. Protein A (PA) has been immobilized by a passive sorption on the microchannel walls. Two bioaffinity assays with human immunoglobulin G (hIgG) as a ligand have been carried out. (i) PA as the receptor and fluorescently labeled hIgG (FITC-hIgG) as the ligand, (ii) PA as the receptor with hIgG as the quantified ligand and fluorescently labeled goat anti-human IgG (FITC-gIgG) as the secondary ligand. One incubation step of the assays took only 5 min instead of hours typical for enzyme-linked immunosorbent assay applications. Calibration curves of the dependence of a fluorescence signal on the hIgG concentration in a sample have been obtained in one step due to a parallel arrangement of microchannels. A mathematical model of the PA-FITC-hIgG complex formation in the chip has been developed. The values of the kinetic constant of the PA-FITC-hIgG binding (k(on)=5.5 m(3) mol(-1) s(-1)) and the equilibrium dissociation constant of the formed complex (K(d)</=3x10(-6) mol m(-3)) have been obtained by fitting to experimental data. The proposed microchip enables fast evaluation of kinetic and equilibrium constants of ligand-receptor bioaffinity pairs and the ligand quantification. As the use of microfluidic chips for immunoassays is often limited by price, we used procedures and chemicals that allow for an inexpensive construction and operation of the microdevice, e.g., temperature assembling as a fabrication technique, detection via an ordinary digital camera, nonspecific polystyrene as a substrate, passive sorption of biomolecules as an immobilization technique, etc.

Effect of specific humoral immunity and some non-specific factors on resistance of volunteers to respiratory coronavirus infection

Thirty-three volunteers were inoculated intranasally with coronavirus 229 E, and their responses monitored by antibody rises, symptomatology and virus excretion. These were related to their pre-trial immune status as indicated by concentrations of specific antibodies and non-specific proteins in serum and nasal washings. Both circulating and local specific antibodies were associated with protection from infection and disease, but only specific IgA antibodies of either type appeared to shorten the period of virus shedding. Although total secretory IgA was significantly associated only with reduction of symptoms, total protein in nasal washings appeared to protect against infection also, indicating that other locally produced proteins, not identified, may be associated with resistance. Two of the many factors which may affect the concentration of circulating and local protective proteins and thus influence the outcome of virus inoculation, namely, sex of the volunteer and the interval since the previous cold, were examined. Male volunteers or volunteers who had had evidence of a recent respiratory infection were less likely to be infected, but if they were infected, they had lower clinical scores and stopped shedding virus earlier than the rest. These groups possessed higher concentrations of specific antibodies and non-specific proteins in their pre-challenge sera and/or nasal washings. The significance of these findings is discussed.

Fatal disseminated adenovirus 11 pneumonia in an agammaglobulinemic patient

Adenovirus type 11, an organism not previously associated with pneumonia, caused the death of a patient with infantile x-linked agammaglobulinemia who had normal cell-mediated immunity. Despite long-standing, regular therapy with immune globulin, his serum lacked neutralizing antibody to the virus. This case confronts the conventional view that viral infections are primarily resisted by cellular immune reactions and reemphasizes the importance of antibody in the host defense against adenoviruses. It further demonstrates the continued vulnerability of such patients to certain pathogens in the presence of presumably adequate standard-dose passive immunization.

Concentration of immunoglobulins in nasal secretion from children with recurrent infections in the upper airways

Concentrations of immunoglobulin G (IgG), IgA, IgE and albumin were determined in nasal secretion from 14 children suffering from chronically recurrent infections in the upper airways and from normal subjects. The only statistically significant difference observed was increased albumin values during infection.