Potency and durability of T and B cell immune responses after homologous and heterologous vector delivery of a trimer-stabilized, membrane-displayed HIV-1 clade ConC Env protein

Introduction

The generation of an HIV-1 vaccine able to induce long-lasting protective immunity remains a main challenge. Here, we aimed to modify next-generation soluble, prefusion-stabilized, close-to-native, glycan-engineered clade C gp140 envelope (Env) trimers (sC23v4 KIKO and ConCv5 KIKO) for optimal display on the cell surface following homologous or heterologous vector delivery.

Methods

A combination of the following modifications scored best regarding the preservation of closed, native-like Env trimer conformation and antigenicity when using a panel of selected broadly neutralizing (bnAb) and non-neutralizing (nnAb) monoclonal antibodies for flow cytometry: i) replacing the natural cleavage site with a native flexible linker and introducing a single amino acid substitution to prevent CD4 binding (*), ii) fusing a heterologous VSV-G-derived transmembrane moiety to the gp140 C-terminus, and iii) deleting six residues proximal to the membrane.

Results

When delivering membrane-tethered sC23v4 KIKO* and ConCv5 KIKO* via DNA, VSV-GP, and NYVAC vectors, the two native-like Env trimers provide differential antigenicity profiles. Whereas such patterns were largely consistent among the different vectors for either Env trimer, the membrane-tethered ConCv5 KIKO* trimer adopted a more closed and native-like structure than sC23v4 KIKO*. In immunized mice, VSV-GP and NYVAC vectors expressing the membrane-tethered ConCv5 KIKO* administered in prime/boost combination were the most effective regimens for the priming of Env-specific CD4 T cells among all tested combinations. The subsequent booster administration of trimeric ConCv5 KIKO* Env protein preserved the T cell activation levels between groups. The evaluation of the HIV-1-specific humoral responses induced in the different immunization groups after protein boosts showed that the various prime/boost protocols elicited broad and potent antibody responses, preferentially of a Th1-associated IgG2a subclass, and that the obtained antibody levels remained high at the memory phase.

Discussion

In summary, we provide a feasible strategy to display multiple copies of native-like Env trimers on the cell surface, which translates into efficient priming of sustained CD4+ T cell responses after vector delivery as well as broad, potent, and sustained antibody responses following booster immunizations with the homologous, prefusion-stabilized, close-to-native ConCv5 KIKO* gp140 Env trimer.

[Atrial septal defect percutaneous transvenous occlusion with the buttoned device]

PURPOSE

To analyse the experience with the use of Sideris' device for percutaneous transvenous occlusion of atrial septal defect (ASD).

METHODS

Thirty six procedures of ASD occlusion were performed in 32 patients; 27 (84.4%) female and five (15.6%) male, mean age of 16 years (4-61). All patients had secundum atrial septal defects with clinical and hemodynamic compromise. The ASD diameter measured < 31 mm and occupied less than 50% of the septal length in all cases. The basic device was used in 28 (87.5%) patients and the self centered model in four (12.5%). The direct implant technique was employed in 15 (41.7%) procedures while in the other 21 (58.3%) an over a wire technique was used. The size of the device was selected according with the Sideris' normogram.

RESULTS

Occlusion of the defect was achieved in 29 patients (90.63%). In two (6.25%) the position of the device was not adequate and in one (3.12%) the device embolized to the pulmonary artery. In these three cases the device was removed surgically during the defect closure. There was neither morbidity nor mortality in this series. Trivial or small residual shunt was detected with color flow mapping in three (9.4%) patients immediately after the procedure. In 22 patients with 12 months follow-up, trivial residual shunt was present in only one (4.5%). Structural modification of the device was detected in one patient, however with complete ASD occlusion and neither clinical nor hemodynamic disturbance.

CONCLUSION

The Sideris' device is safe and efficient for ASD occlusion in selected patients. Although there is a relatively high incidence of residual shunt immediately after the procedure, the shunt itself tends to become smaller or disappear during the follow-up and it does not preclude clinical and hemodynamic improvement.

[Percutaneous closure of interatrial defect using the buttoned double-disk prosthesis]

BACKGROUND

Surgical repair is the procedure of choice for atrial septal defect correction. Even though surgical mortality is low (< 1%), morbidity is significant (anesthesia, thoracotomy, cardiopulmonary bypass, longer hospitalization and intensive care unit monitoring). Transcatheter methods to occlude atrial septal defects have been in development during the last two decades. We report our experience in Italy with the Sideris buttoned double-disk device.

METHODS

From March 1992 to April 1993, 14 patients aged 20 months to 52 years, weight 10 to 82 kg, underwent transcatheter atrial septal defect occlusion with the Sideris buttoned device. The buttoned device is a miniaturized two disk device introduced through small venous sheaths (8-9 F). The diameter of atrial septal defects by echocardiography varied between 9 and 23 mm, while the balloon stretched diameter of the defects varied between 13 and 24 mm. The devices selected were 19 +/- 4 mm larger than the stretched diameter of the defect, but less than the total length of the septum (33-56 mm) by echo.

RESULTS

Pulmonary-to-systemic flow ratio varied between 1.5 to 4.0. Mean pulmonary artery pressure varied between 10 and 24 mmHg (mean value 17 +/- 3.5 mm Hg). The relationship between different atrial septal defect measurements (echo, shunt flow, stretched diameter) was statistically analysed: transthoracic echo diameter had a good correlation with the balloon stretched diameter (r = 0.63, p < 0.001). The atrial septal defect was occluded in 12 patients (86% success rate). There was one early "unbuttoning" which was surgically corrected with success. The other patient underwent surgical correction 3 months later because of unsuitability for transcatheter closure. Minimal residual shunt detected by color flow mapping at 1 month follow-up was seen in 4 patients (33%). No complications occurred in any of our patients.

CONCLUSIONS

This initial experience with the Sideris buttoned double-disk device demonstrated that transcatheter closure of atrial septal defect is feasible and effective. It can be accomplished through small introducing sheaths. Further clinical trials are justified. This method could become the procedure of choice for the correction of small ASDs.

Transvascular intracardiac applications of a miniaturized phased-array ultrasonic endoscope. Initial experience with intracardiac imaging in piglets

BACKGROUND

Recent advances in miniaturization of phased-array and mechanical ultrasound devices have resulted in exploration of alternative approaches to cardiac and vascular imaging in the form of transesophageal or intravascular imaging. Preliminary efforts in adapting phased-array endoscopes designed for transesophageal use to a transvascular approach have used full-sized phased-array devices introduced directly into the right atrium in open-chested animals. The purpose of this study was to assess the feasibility of using a custom-made, very small phased-array endoscope for intracardiac imaging introduced intravascularly through a jugular venous approach in young piglets.

METHODS AND RESULTS

Experimental atrial septal defects created in four piglets (3-4 weeks old) had been closed with a buttoned atrial septal defect closure device consisting of an occluder in the left atrium and a counteroccluder in the right atrium. Five to 15 days after atrial septal defect closure, the piglets were returned to the experimental laboratory, where a 6.3-mm, 17-element, 5-MHz phased-array probe mounted on a 4-mm endoscope was introduced through a cutdown incision of the external jugular vein and advanced to the right atrium. From the right atrium all four cardiac chambers, their inflows and outflows, and all four valves were well imaged with minimal superior and inferior rotation. High-resolution imaging of the atrial septum defined with anatomical accuracy, later verified by autopsy, the exact placement of both the occluder and counteroccluder in the left and right sides of the atrial septal defects and the absence of any shunting across the atrial septum in any of the four animals.

CONCLUSIONS

Our efforts indicate that transvascular passage of small phased-array probes can be easily accomplished and is a promising technique for detailed visualization of cardiac structures. This approach may provide an alternative to transesophageal echocardiography, particularly for guiding interventional procedures such as placement of transcatheter closure devices in pediatric patients.

Green light phototherapy in newborn infants with ABO hemolytic disease

The efficacy of fluorescent green light phototherapy was compared with that of blue light phototherapy in the treatment of full-term infants with hemolytic disease and jaundice caused by ABO incompatibility. The efficacy of the treatment was expressed as actual (milligrams per hour) and quantum (milligrams per hour per square centimeter per megawatt) efficiency, taking into account the differential emission of energy from the green versus the blue fluorescent tubes. No statistically significant difference in the rate of serum bilirubin photodegradation was found between the two groups after treatment for 84.6 +/- 14.1 hours versus 81.5 +/- 14.2 hours with the green and the blue phototherapy, respectively. These results, coupled with the known effects of the blue light on the genetic apparatus of mammalian cells, support the application of the green light phototherapy for the treatment of neonatal hyperbilirubinemia caused by ABO incompatibility.

Green or blue light phototherapy for neonates with hyperbilirubinaemia

A total of 262 neonates were treated with green (350-650 nm) or blue (300-600 nm) light phototherapy for a similar length of time. There was no significant difference in the rate of bilirubin photodegradation between the groups.

Action of PGI2 analogs on the pulmonary and systemic circulations in the conscious newborn lamb

Previous work (Lock et al., J. Pharm . Exp. Ther. 215:156, 1980) has shown that conventional screening procedures for vasoactive PGI2 analogs were little value in predicting pulmonary vasodilator activity in the newborn lamb. To gain a better insight into the structural requirements for pulmonary vasoactivity and possibly identify useful compounds for the management of neonatal pulmonary hypertensive disorders, we have tested the following PGI2 analogs in normoxic and hypoxic newborn lambs: 15(S)-9-deoxy-15-methyl-9 alpha,6- nitrilo -PGF1 (analog I); 9-deoxy-9 alpha,5- nitrilo -PGF1 (analog II); (6S, 15S)-15-methyl-PGI2 (analog III); and ( 6R , 15S)-15-methyl-PGI1 (analog IV). A prostaglandin analog mimicking PGI2 (compound BW245C ; (+/-)-5-(6- carboxyhexyl )-1-(3-cyclohexyl-3-hydroxypropyl)hydantoin ) was tested as well. Compounds were injected into a branch pulmonary artery and any local pulmonary effect could be assessed from the change in the ratio of blood flow to the injected lung over total flow. None of the analogs tested proved to be a selective pulmonary dilator. BW245C was a potent peripheral vasodilator (threshold around 0.5 microgram/kg) and indirectly lowered pulmonary vascular resistance through its systemic effects. Analog I also dilated the systemic circulation, but only at the highest dose tested (100 micrograms/kg). The latter finding is surprising because it was previously shown that the parent, non-methylated compound is a fairly potent and selective pulmonary vasodilator. Analog II and IV were inactive at a dose up to, respectively, 30 and 20 micrograms/kg. Analog III, on the other hand, weakly constricted the systemic circulation at a dose of 10 micrograms/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Primary peptic ulcer in childhood. Psychosocial, psychological and psychiatric aspects

Twenty-five children with radiologically confirmed primary peptic ulcers were investigated. All patients suffered from duodenal ulcer and there was an unexpected female preponderance. The frequency of introverted personalities was greater in the patients than in the controls. Five patients suffered from psychiatric disorders, three had histories of suicidal attempts and three reported homosexual experiences. Six patients had nicknames. Eight patients had been operated on for appendicitis. The above parameters were negative in all control cases. The patients had lower mean IQ, worse adaptation to school, more anxious and overprotective parents, higher frequency of faddiness in food and lower frequency of nail-biting than the controls. The onset of symptoms was preceded by psychotraumatic events in eight cases. The findings suggest that the manifestation of the genetic background of duodenal ulcer is strongly influenced by environmental factors and factors associated with the personality of the patients.