Cyclosporine A Decreases Dryness-Induced Hyperexcitability of Corneal Cold-Sensitive Nerve Terminals

Cyclosporine A (CsA) is used for the treatment of dry eye (DE) with good clinical results, improving tear secretion and decreasing subjective symptoms. These effects are attributed to the improved tear film dynamics, but there are no data on the effect of CsA on the abnormal sensory nerve activity characteristic in DE. Our purpose was to evaluate the CsA effect on the enhanced activity of corneal cold thermoreceptors in a tear-deficient DE animal model using in vitro extracellular recording of cold thermoreceptors nerve terminal impulses (NTIs) before and in the presence of CsA. NTI shape was also analyzed. Blinking frequency and tearing rate were also measured in awake animals before and after topical CsA. CsA increased the tearing and blinking of treated animals. CsA significantly decreased the peak response to cold of cold thermoreceptors. Neither their spontaneous NTIs discharge rate nor their cooling threshold were modified. CsA also seemed to reverse some of the changes in NTI shape induced by tear deficiency. These data suggest that, at least in part, the beneficial clinical effects of CsA in DE can be attributed to a direct effect on sensory nerve endings, although the precise mechanisms underlying this effect need further studies to be fully clarified.

Assessment of Visual Quality Improvement as a Result of Spectacle Personalization

Personalized spectacles customized according to an individual's facial anatomy were developed to provide enhanced visual performance and overall comfort when compared to standard spectacles. In this comparative crossover trial, each subject was randomly assigned to wear either personalized spectacles or standard spectacles for two weeks and then tried the second pair for another two weeks. Visual acuity and reading speed were measured, and visual quality and comfort were assessed using specific questionnaires. The correlation of the wearing parameters with the subjects' satisfaction was calculated. According to our results, the subjects wearing personalized glasses reported significantly less experience of swaying and significantly higher overall satisfaction compared to those wearing the control spectacles. At the end of the study, 62% of subjects preferred the personalized spectacles, and visual quality was the primary reason for their spectacle preference followed by wearing comfort. The difference from the ideal cornea-vertex distance was significantly lower when wearing the personalized spectacles compared to the control frames. In addition, the absolute value of the difference from the ideal cornea-vertex distance was significantly correlated with patient satisfaction. These results suggest that personalized spectacles, customized according to an individual's facial anatomy for the ideal wearing parameters, result in both visual and comfort advantages for wearers.

Intraocular neutralizing antibodies against aflibercept in patients with age related macular degeneration

PURPOSE

To detect immunoglobulins in aqueous humour of AMD patients after repeated administration of intravitreal aflibercept.

PATIENTS AND METHODS

Twenty-one patients (age: 77.85 ± 9.21 years) previously treated with intravitreal aflibercept due to wet type age-related macular degeneration (AMD group) and 18 age-matched control subjects (age: 69.75 ± 12.67 years) were included in this study. Patients in the AMD group received a mean of 5 intravitreal injections (min: 1 max: 17) prior to the cataract surgery. Samples of aqueous humour (50 μl) were obtained by anterior chamber paracentesis as the first step of routine cataract surgery. The IgG content of the samples was analysed by an in-house developed ELISA system.

RESULTS

A significant increase in nonspecific IgG levels in the AMD group was detected compared to the control group (13.37 ± 6.65 vs. 9.44 ± 6.55 μg/ml; p = 0.03). In 11 patients, intraocular anti-aflibercept immunoglobulins could be detected (0.05 ± 0.01 μg/ml) which was significantly higher than the limit of detection for anti-aflibercept (0.04 μg/ml; p = 0.001). No correlation was found between the number of injections or the type of CNV and the aqueous level of anti-aflibercept (r = 0.02; p = 0.95).

CONCLUSION

According to our results, penetration of non-specific systemic antibodies through the impaired blood-retinal barrier is higher in patients with neovascular AMD than in subjects with an intact structural barrier. Evaluation of neutralizing antibodies to anti-VEGF agents in the aqueous humour can lead us to understanding tachyphylaxis and changes in intraocular immune mechanisms due to AMD.

Matrix Metalloproteinase-2 Impairs Homing of Intracoronary Delivered Mesenchymal Stem Cells in a Porcine Reperfused Myocardial Infarction: Comparison With Intramyocardial Cell Delivery

Background

Intracoronary (IC) injection of mesenchymal stem cells (MSCs) results in a prompt decrease of absolute myocardial blood flow (AMF) with late and incomplete recovery of myocardial tissue perfusion. Here, we investigated the effect of decreased AMF on oxidative stress marker matrix metalloproteinase-2 (MMP-2) and its influence on the fate and homing and paracrine character of MSCs after IC or intramyocardial cell delivery in a closed-chest reperfused myocardial infarction (MI) model in pigs.

Methods

Porcine MSCs were transiently transfected with Ad-Luc and Ad-green fluorescent protein (GFP). One week after MI, the GFP-Luc-MSCs were injected either IC (group IC, 11.00 ± 1.07 × 10⁶) or intramyocardially (group IM, 9.88 ± 1.44 × 10⁶). AMF was measured before, immediately after, and 24 h post GFP-Luc-MSC delivery. In vitro bioluminescence signal was used to identify tissue samples containing GFP-Luc-MSCs. Myocardial tissue MMP-2 and CXCR4 receptor expression (index of homing signal) were measured in bioluminescence positive and negative infarcted and border, and non-ischemic myocardial areas 1-day post cell transfer. At 7-day follow-up, myocardial homing (cadherin, CXCR4, and stromal derived factor-1alpha) and angiogenic [fibroblast growth factor 2 (FGF2) and VEGF] were quantified by ELISA of homogenized myocardial tissues from the bioluminescence positive and negative infarcted and border, and non-ischemic myocardium. Biodistribution of the implanted cells was quantified by using Luciferase assay and confirmed by fluorescence immunochemistry. Global left ventricular ejection fraction (LVEF) was measured at baseline and 1-month post cell therapy using magnet resonance image.

Results

AMF decreased immediately after IC cell delivery, while no change in tissue perfusion was found in the IM group (42.6 ± 11.7 vs. 56.9 ± 16.7 ml/min, p = 0.018). IC delivery led to a significant increase in myocardial MMP-2 64 kD expression (448 ± 88 vs. 315 ± 54 intensity × mm², p = 0.021), and decreased expression of CXCR4 (592 ± 50 vs. 714 ± 54 pg/tissue/ml, p = 0.006), with significant exponential decay between MMP-2 and CXCR4 (r = 0.679, p < 0.001). FGF2 and VEGF of the bioluminescence infarcted and border zone of homogenized tissues were significantly elevated in the IM goups as compared to IC group. LVEF increase was significantly higher in IM group (0.8 ± 8.4 vs 5.3 ± 5.2%, p = 0.046) at the 1-month follow up.

Conclusion

Intracoronary stem cell delivery decreased AMF, with consequent increase in myocardial expression of MMP-2 and reduced CXCR4 expression with lower level of myocardial homing and angiogenic factor release as compared to IM cell delivery.

[Ocular surface squamous neoplasia]

To summarize actual knowledge on epidemiology, etiology, pathology, clinical apparence and treatment of ocular surface squamous neoplasias. We summarize up-to-date literature on conjunctival intraepithelial neoplasia and invasive squamous cell carcinoma and present some own cases. Ocular surface squamous neoplasia is the most common malignant ocular surface tumor and the third most common ocular malignancy following malignant melanoma and lymphoma. In spite of its low malignant potential, in advanced stages it may reduce visual acuity significantly or even the eye globe has to be removed. In case of metastasis it may also be life-threatening. As local recurrences of ocular surface squamous neoplasias may occur, knowledge of intra- and postoperative adjuvant treatment options are indispensable and regular control examinations are necessary. Identification and adequate treatment of ocular surface squamous neoplasias are necessary in order to avoid its progression and to prevent recurrences. Orv Hetil. 2017; 158(51): 2011-2022.

[Relationship between corneal surface temperature and air flow conditions during refractive laser eye surgery using three different excimer lasers]

INTRODUCTION

Thermal conditions during photorefractive keratectomy might be an important issue related to the corneal wound healing and long-term outcomes.

AIM

Authors tried to find out the importance of temperature conditions during the treatment.

METHOD

One eye of 90 patients has been included into the study. Photorefractive keratoctomy was applied with Carl Zeiss MEL 70, MEL 80 and Wavelight Allegretto excimer lasers. EBRO TLC 730 infrared thermometer was used for the measurement of surface temperature of the cornea before epithelial removal, as well as before and after the treatment. Average age of the patients was 25.5 ± 3 yr. Average myopic correction was -3.2 ± 0.8 Dpt.

RESULTS

Statistically significant difference was found in temperature change between MEL 80 and the other two types of excimer laser devices.

CONCLUSIONS

Different air flow conditions of the smoke removal system might have an influence on changes of the corneal temperature during treatment, but the refractive results were not influenced by this issue. Orv. Hetil., 2016, 157(43), 1717-1721.

[Impact of crosslinking on corneal epithelial healing]

INTRODUCTION AND AIM

To analyse the effect of crosslinking (CXL) on corneal epithelial healing.

PATIENTS AND METHOD

39 keratoconus patients following CXL and 11 patients following PRK were enrolled in this study. 21, 45 and 69 hours after CXL and 16, 37 and 61 hours following PRK slitlamp photographs were taken using fluorescein staining and the size of the epithelial defect and the time of epithelial closure was determined. As the observation time-points differed in both groups, the size of the epithelial defect following PRK was calculated for the time points used for analysis of CXL patients. These data were compared using chi-quadrat test.

RESULTS

Following crosslinking, epithelial closure occured within 3, following PRK within 4 days. In the area of epithelial erosion 45 and 69 hours after CXL or PRK treatment statistically significant difference (p = 0.005 and p<0.001) was verified.

CONCLUSION

Our results show beneficial effect of crosslinking on corneal epithelial healing. Orv. Hetil., 2017, 158(10), 376-379.

[Two cases of phototherapeutic keratectomy treatment of the recurrent corneal erosion caused by alkali burn]

BACKGROUND

Four eyes of two patients were injured simultaneously by industrial alkali while working. One eye of both patients healed without later consequences.

PATIENTS AND METHODS

Two eyes were treated with phototherapeutic keratectomy (PTK) because of recurrent corneal erosion syndrome caused by alkali burn.

RESULTS

In both cases reepithelisation of the cornea was completed by the end of the 1st postoperative week, the injured persons were able to work again. No recurrence was experienced in the next 6 months of follow-up.

CONCLUSION

With these cases the authors would like to draw attention to the possible complications, as well as the importance of careful balancing and adequate management.

Aromatase and estrogen receptor beta expression in the rat olfactory bulb: Neuroestrogen action in the first relay station of the olfactory pathway?

The expression pattern of aromatase (ARO), the enzyme converting androgens to estrogens, was analyzed in the olfactory bulb of adult male rats and was compared with the distribution of estrogen receptor beta (ERbeta), the main estrogen receptor isoform expressed in this brain region. A strong ARO immunolabeling obtained with a specificity tested antibody was observed in juxtaglomerular neurons of the glomerular layer and a weaker immunoreaction was detected in the mitral cell layer of the main olfactory bulb, while the granule cell layer of the main olfactory bulb as well as all layers in the accessory olfactory bulb showed faint immunolabeling. Fluorescence double labeling experiments revealed that ARO detected in juxtaglomerular neurons of the main olfactory bulb colocalized with tyrosine hydroxylase (TH) and glutamic acid decarboxylase 67 (GAD67), while no colocalization between ARO and the calcium binding proteins calretinin (CR) and calbindin (CB) was observed. Furthermore, the TH immunoreactive neurons expressed metabotropic glutamate receptor 1 (mGluR1) too. ERβ immunoreactivity, in contrast to ARO, was detected in all layers of both the main and accessory olfactory bulb. In the glomerular layer of the main olfactory bulb it was expressed in TH and GAD67 containing juxtaglomerular neurons, and it colocalized with CR, CB and even with glial fibrillary acidic protein too. Our morphological findings suggest that ARO expression is a novel feature of dopaminergic/GABAergic juxtaglomerular neurons in the adult rat main olfactory bulb, and raise the possibility that ARO activity may change in function of olfactory input via mGluR1. In situ estrogen production in the olfactory bulb in turn may modulate interglomerular circuits through ERbeta.

Femtosecond laser-assisted cataract surgery in management of phacomorphic glaucoma

PURPOSE

To report the use of femtosecond laser-assisted cataract surgery in management of phacomorphic glaucoma.

METHODS

An 89-year-old patient developed acute phacomorphic glaucoma in her right eye with elevated intraocular pressure (62 mm Hg), shallow anterior chamber, and mature cataract. After conservative antiglaucoma therapy and Nd:YAG iridotomy, femtosecond laser-assisted cataract surgery was performed. A Malyugin ring was implanted for mechanical pupil dilatation and a 4.8-mm capsulorrhexis and lens fragmentation was performed using a femtosecond laser system (Alcon LenSx Inc., Aliso Viejo, CA) followed by in-the-bag intraocular lens implantation.

RESULTS

Intact 4.8-mm capsulorrhexis and successful lens fragmentation could be performed using femtosecond laser. After cataract surgery, the patient's visual acuity increased from hand motions to 0.4 (Snellen 4/10) and the intraocular pressure returned to normal range without antiglaucoma drop therapy.

CONCLUSIONS

The results indicate that femtosecond laser can be successfully used in certain cases of phacomorphic glaucoma, even if mechanical pupil dilatation is needed.

17β-estradiol attenuates injury-induced microglia activation in the oculomotor nucleus

Recent studies provide increasing data indicating the prominent role of estrogens in protecting the nervous system against the noxious consequences of nerve injury. It is also clear that in the process of nerve injury and recovery not only the neurons, but the glial cells are also involved and they are important components of the protective mechanisms. In the present article the effect of 17β-estradiol on injury-induced microglia activation was studied in an animal model. Peripheral axotomy of the oculomotor neurons was achieved by the removal of the right eyeball including the extraocular muscles of ovariectomized adult mice. The time course and the extent of microglia activation was followed by the unbiased morphometric analysis of CD11b immunoreactive structures within the oculomotor nucleus. The first sign of microglia activation appeared after 24 h following injury, the maximal effect was found on the fourth day. In ovariectomized females hormone treatment (daily injection of 17β-estradiol, 5 μg/100 g b.w.) decreased significantly the microglia reaction at postoperative day 4. Our results show that microglia response to nerve injury is affected by estradiol, that is these cells may mediate some of the hormonal effects and may contribute to protective mechanisms resulting in the structural and functional recovery of the nervous system.

Computer-aided structure analysis of an epimerized dehydroepiandrosterone derivative and its biological effect in a model of reactive gliosis

The naturally occurring steroid dehydroepiandrosterone (DHEA) is reported to reduce glial fibrillary acidic protein (GFAP) overexpression in a model of reactive gliosis due to its conversion to estradiol by the enzyme aromatase. In the present study we examined the biological effect of a new epimerized derivative of DHEA, 16alpha-iodomethyl-13alpha-dehydroepiandrosterone derivative (16alpha-iodomethyl-13alpha-DHEAd, 16alpha-iodomethyl-13alpha-androst-5-en-3beta,17beta-diol), using the same model system, and compared the 3D structure of this molecule with that of DHEA and two steroidal type aromatase inhibitors, formestane and exemestane. The synthetic compound, in contrast to the reported effect of DHEA, was able to reduce GFAP overexpression only if the enzyme aromatase was inhibited. Data obtained from computational calculations fortified by X-ray crystallography revealed that contrary to the nearly planar sterane framework of DHEA, the synthetic derivative 16alpha-iodomethyl-13alpha-DHEAd has a bent sterane skeleton, resulting in a 3D structure that is similar to that of formestane or exemestane. Moreover, 16alpha-iodomethyl-13alpha-DHEAd resulted to be metabolically more stable than DHEA. The results suggest that epimerization of the sterane skeleton of DHEA inclines the plane of the D ring, leading to a significantly altered biological activity. The synthetic molecule has a DHEA-like effect on GFAP overexpression when the enzyme aromatase is inhibited and the naturally occurring DHEA is ineffective in this respect. On the other hand, based on their structural similarity it can be hypothesized that 16alpha-iodomethyl-13alpha-DHEAd applied alone might have a biological effect similar to that of formestane or exemestane.

Estradiol-induced synaptic remodeling of tyrosine hydroxylase immunopositive neurons in the rat arcuate nucleus

Gonadal steroids induce synaptic plasticity in several areas of the adult nervous system. In the arcuate nucleus of adult female rats, 17beta-estradiol triggers synaptic remodeling, resulting in a decrease in the number of inhibitory synaptic inputs, an increase in the number of excitatory synapses, and an enhancement of the frequency of neuronal firing. In the present paper, we studied the specificity of hormonal effects by determining the changes in synaptic connectivity of tyrosine hydroxylase (TH) immunoreactive (IR) neurons in the arcuate nucleus. We combined pre-embedding TH and post-embedding gamma-aminobutyric acid (GABA) immunostaining, and performed unbiased stereological measurements in gonadectomized and 17beta-estradiol-treated rats. We conclude that the synaptic connectivity of the TH-IR neurons is different from the other, nonlabeled population, and the response to estradiol is not uniform. TH-IR (dopaminergic) arcuate neurons of both male and female rats have more GABAergic (inhibitory) axosomatic inputs than the nondopaminergic population. Our study shows that the effect of 17beta-estradiol is sex and cell specific in the sense that not all arcuate neurons are affected by the structural synaptic remodeling. In ovariectomized females hormone treatment decreased the numerical density of GABAergic axosomatic synapses on TH-IR, but not on nondopaminergic, neurons, whereas in orchidectomized males, 17beta-estradiol treatment increased inhibitory synapses onto nondopaminergic neurons but did not affect the number of inhibitory terminals onto TH-IR neurons. The hormone-induced plastic changes in synaptic connectivity of TH-IR neurons may serve as the morphological basis for the cyclical regulation of the anterior pituitary.

Fluctuation of synapse density in the arcuate nucleus during the estrous cycle

The hypothalamic arcuate nucleus integrates different hormonal and neural signals to control neuroendocrine events, feeding, energy balance and reproduction. Previous studies have shown that in adult female rats the arcuate nucleus undergoes a cyclic fluctuation in the number of axo-somatic synapses during the estrous cycle, in parallel to the variation of ovarian hormone levels in plasma. In the present study we have used an unbiased stereological analysis in conjunction with postembedding immunocytochemistry to assess whether the synaptic remodeling during the estrous cycle in rats is specific for certain types of synapses. Our findings indicate that there is a significant decrease in the number of GABAergic axo-somatic synapses on proestrus afternoon and estrus day compared with other days of the estrous cycle. This decrease in GABAergic synapses is accompanied by an increase in the number of dendritic spine synapses. The synaptic density appears to cycle back to proestrus morning values on metestrus day. In contrast, the number of synapses on dendritic shafts does not change during the cycle. These results indicate that a rapid and selective synaptic turnover of arcuate synapses occurs in physiological circumstances.

Hepatitis B virus e antigen specific epitopes and limitations of commercial anti-HBe immunoassays

Current commercial hepatitis B virus (HBV) anti-HBe immunoassays are designed so that anti-HBe is detectable only in the absence of excess HBeAg. Recently, with the use of direct anti-HBe assays, anti-HBe was detected in individuals who had been seropositive for several years for HBeAg [Maruyama et al. (1993) J. Clin. Invest. 91:2586-2595]. Although anti-HBe seroconversion does not necessarily indicate subsequent HBeAg clearance, the ability to detect earlier anti-HBe seroconversion could have clinical significance for monitoring patients undergoing HBV immunotherapy (e.g., alpha interferon therapy). Because the HBeAg and the HBcAg share 149 amino acids, an anti-HBe assay must distinguish anti-HBe from anti-HBc antibodies. Although the HBV HBeAg and HBcAg display distinct immunogenic determinants, much remains unknown regarding the complete epitope spectrum specific to each antigen. The goal of this study was 3-fold. The first objective was to identify HBeAg specific linear epitopes. The second objective was to design an anti-HBe immunoassay capable of detecting anti-HBe specific antibody in the presence of excess HBeAg. The third objective was to characterize early anti-HBe seroconversion antibodies. The major linear epitope residing in the HBeAg amino acid sequence was mapped and 2 novel minor epitopes (delta, gamma) which appear to be HBeAg specific have been identified. An anti-HBe immunoassay capable of detecting anti-HBe specific antibody in the presence of excess HBeAg was designed. Finally, it was found that early anti-HBe seroconversion antibodies appear to be conformational, whereas later seroconversion, more typically associated with the clearance of HBeAg, is characterized by the presence of antibodies to the linear HBeAg epitopes.

Use of a novel hepatitis C virus (HCV) major-epitope chimeric polypeptide for diagnosis of HCV infection

The genome of hepatitis C virus (HCV) consists of seven functional regions: the core, E1, E2/NS1, NS2, NS3, NS4, and NS5 regions. The U. S. Food and Drug Administration-licensed 2.0G immunoassay for the detection of anti-HCV uses proteins from the core, NS3, and NS4 regions (McHutchinson et al., Hepatology 15:19-25, 1992). The 3.0G enzyme-linked immunosorbent assay includes the protein from the NS5 region (Uyttendaele et al., Vox Sang. 66:122-129, 1994). The necessity of detecting antibodies to viral envelope proteins (E1 and E2) and to different genotype samples has been demonstrated previously (Chien et al., Lancet 342:933, 1993; Lok et al., Hepatology 18:497-502, 1993). In this study we have attempted to improve the sensitivity of the anti-HCV assay by developing a single multiple-epitope fusion antigen (MEFA; MEFA-6) which incorporates all of the major immunodominant epitopes from the seven functional regions of the HCV genome. A nucleic acid sequence consisting of proteins from the viral core, E1, E2, NS3, NS4, and NS5 regions and different subtype-specific regions of the NS4 region was constructed, cloned, and expressed in yeast. The epitopes present on this antigen can be detected by epitope-specific monoclonal and polyclonal antibodies. In a competition assay, the MEFA-6 protein competed with 83 to 96% of genotype-specific antibodies from HCV genotype-specific peptides. This recombinant antigen was subsequently used to design an anti-HCV chemiluminescent immunoassay. We designed our assay using a monoclonal anti-human immunoglobulin G antibody bound to the solid phase. Because MEFA-6 is fused with human superoxide dismutase (h-SOD), we used an anti-human superoxide dismutase, dimethyl acridinium ester-labeled monoclonal antibody for detection. Our results indicate that MEFA-6 exposes all of the major immunogenic epitopes. Its excellent sensitivity and specificity for the detection of clinical seroconversion are demonstrated by this assay.

Modification of a receptor-binding surface of epidermal growth factor (EGF): analogs with enhanced receptor affinity at low pH or at neutrality

Six mutants of human epidermal growth factor (EGF), which carry single point substitutions within a surface patch proposed to juxtapose the bound receptor, were prepared and characterized for receptor affinity and mitogenicity. Receptor affinities relative to EGF are G12Q > H16D > Y13W > Q43A approximately = H16A approximately = EGF >> L15A. Notably, the reduced receptor affinity of mutant L15A indicates that Leu15 probably contributes substantially to receptor binding whereas unaltered receptor affinities observed for analogs H16A and Q43A indicate that neither His16 nor Gln43 contributes significantly to this interaction. On the other hand, the observed enhanced receptor affinities of analogs G12Q, Y13W and H16D highlight surface loci where additional productive receptor-binding contacts can be introduced. Interestingly, at acidic pH analog H16A reveals substantially greater receptor affinity than that of EGF, a property which may offer enhanced therapeutic utility in acidic environments in vivo.

Lymphocyte proliferative responses to human immunodeficiency virus antigens in vitro

All HIV seronegative (HIV Ab-) and most HIV seropositive (HIV Ab+) individuals' lymphocytes failed to proliferate in primary cultures in response to purified HIV or to recombinant envelope and core antigens of HIV, even in the presence of recombinant interleukin 2 (rIL-2). Most HIV Ab- and HIV Ab+ individuals' lymphocytes, however, could proliferate or be induced by rIL-2 to proliferate in response to lysates of Escherichia coli or Saccharomyces cerevisiae. These findings indicate selective defects in lymphocyte proliferative responses to HIV antigens before the development of AIDS in which lymphocytes are unable to proliferate in response to any antigens. These defects in cell-mediated immune responses to HIV antigens are likely to play an important role in the pathobiology of HIV infections. Although intact HIV or glycosylated gp120 envelope protein of HIV are involved in these defects, a non-glycosylated recombinant form of the HIV gp120 envelope (ENV2-3) and p25 core proteins did not inhibit antigen- or mitogen-driven lymphocyte proliferation.

Characterization of recombinant human epidermal growth factor produced in yeast

Four different forms of human epidermal growth factor (h-EGF) are found in the culture medium of a recombinant strain of Saccharomyces cerevisiae. These forms were characterized after purification using reverse-phase high-performance liquid chromatography. The most abundant form of secreted recombinant h-EGF has leucine at the carboxyl terminus and is identical with gamma-urogastrone. A second species is identical with the most abundant form except that it lacks the carboxyl-terminal leucine. This form appears to be the product of a carboxypeptidase found in the growth medium. The other two forms of recombinant h-EGF are the respective oxidation products of the above where the single methionine residue has been converted to methionine sulfoxide. These four forms of recombinant h-EGF are fully active; they bind to the EGF receptor of A431 cells as well as stimulate mitotic activity of human foreskin fibroblasts with equal specific activity. The location of the disulfide bonds in the predominant form of recombinant h-EGF was determined following digestion with thermolysin. The amino acid compositions of the resulting peptides showed that the placement of disulfide bonds in recombinant h-EGF is identical with that in murine EGF.

Antigenicity and immunogenicity of domains of the human immunodeficiency virus (HIV) envelope polypeptide expressed in the yeast Saccharomyces cerevisiae

Expression vectors were constructed for the production of various domains of the envelope gene product of the SF-2 isolate of human immunodeficiency virus (HIV) in the yeast Saccharomyces cerevisiae. Serum specimens from HIV seropositive blood donors reacted in immunoblot assays with recombinant polypeptides from both the gp120 and gp41 coding regions of env. Polypeptides from both domains were purified and injected into experimental animals. Antibodies raised in rabbits to env-2, a recombinant polypeptide representing the majority of the protein moiety of gp120, reacted with fully glycosylated native gp120 of HIV-SF2 virions. In addition, these env-2 antisera showed reactivity with viral gp120 of divergent HIV isolates. A 121 amino acid polypeptide (env-5), representing the region of gp41 stretching between the two hydrophobic domains of the protein, elicited antibodies in rabbits that reacted with glycosylated, native gp41. Thus, selected domains of the HIV env gene expressed in genetically engineered yeast, are recognized by sera from HIV infected humans, elicit antibodies that react with native HIV glycoproteins and provide a source of envelope antigens for evaluation as potential subunit vaccines for HIV.