Noveen D. Das

Adherence properties of Pseudomonas pili to epithelial cells of the human cornea.

In vitro adherence of Pseudomonas fluorescens organisms to the human cornea is correlated with bacterial pili. The role of pili in the attachment to human corneal epithelial cells was studied in an in vitro adherence assay system. A homogeneous, purified pilin preparation showed a molecular weight of 16,500 on SDS-polyacrylamide gels. Within 5 minutes incubation, 5.5 pg of pilin adhere to 15,000 epithelial cells. When epithelial cells were preincubated with purified pilin, a subsequent decrease in adherence of labeled pilin was noted. It appears that pili mediate adherence of Pseudomonas organism to human cornea.

Ornithine Decarboxylase in Developing Neonatal Rabbit Ocular Tissue

The specific activity of ornithine decarboxylase (ODC) was assessed in rabbit ocular tissue from 2 to 15 days postnatal. ODC levels in cornea were low, but significant at 2 days, and decreased slightly with time. Activity was not detectable in lens tissue. On the other hand, in retina, ODC decreased from fairly high specific activity to nil in the 1st week after birth. Ciliary body paralleled retina but at a lower level. In contrast, ODC specific activity in the vitreous body rose 25-fold between day 5 and 15. These temporal changes are discussed in terms of neonatal ocular development.

Immunohistochemical Localization of Phosphatidylinositol-4,5-Bisphosphate in the Rat Lens

We have attempted to localize immunohistochemically phosphatidylinositol-4,5-bisphosphate (PIP2) in rat lens tissue using affinity purified rabbit anti-PIP2 antibodies. Evidence indicates that PIP2 is localized to the lens epithelial cells but appears to be absent from the lens fiber cells.

Production of hybridomas secreting antibodies to the cornea

Major controversies exist in the literature on the presence of blood group antigens on the endothelial and stromal layers of the cornea, and the importance of major histocompatibility typing for keratoplasty. Antibodies were raised in BALB/C mice against water soluble proteins of corneal epithelium. Following fusion of spleen cells with myeloma cells (Sp2/0-Ag14) hybrid colonies were maintained in HAT selective medium. The supernates of each colony were measured and screened for antibody production by radioimmunoassay. Gel electrophoresis of the antigen showed nine major bands. The antibodies were partially characterized by cross reaction against other soluble corneal fractions.

Changes in immunoreactivity in S-antigen-induced pinealitis

Changes in immunoreactivity in rat pineal gland were investigated in S‐antigen (S‐Ag)‐induced pinealitis. Anti‐S antibodies were used to study the accessibility of pathogenic epitopes in the organ, and phosphatidyl inositol 4, 5‐bisphospate (PI[4,5]P2) antibodies were chosen to study changes in functional phospholipid in membranes. Control pineal gland (without inflammation) did not show much reactivity toward these antibodies. Immunoreactivity toward both antibodies was markedly increased throughout the organ at the peak of inflammation and decreased almost to control level in the postinflammatory stage. The rise and fall of immunoreactivity were attributed to changes in the accessibility of antigenic sites rather than changes in the amounts of S‐Ag and P(4, 5)P2 The transient enhancement in immunoreactivity, probably consequential to tissue damage, suggests that the pineal gland, unlike the retinal photoreceptors, is capable of quick repair of tissue.

Hybridoma antibodies to insoluble antigens of the corneal epithelium

Human corneal epithelial water insoluble proteins were used to immunize mice. Immune splenocytes were fused with Sp 2/0-Ag14 mouse myeloma cells by 40% PEG. Hybridoma antibodies obtained by somatic cell fusion were tested by radioimmunoassay. Supernatants from antibody positive hybrid colonies were used in immunofluorescence and crossreaction assays to locate and characterize corneal epithelial antigens. At least three distinct epithelial cell antigens were detected, one of which cross-reacts with rabbit corneal epithelial cells.