Antigen-loaded flagellate bacteria for enhanced adaptive immune response by intradermal injection

Since the skin limits the distribution of intradermal vaccines, a large number of dendritic cells in the skin cannot be fully utilized to elicit a more effective immune response. Here, we loaded the antigen to the surface of the flagellate bacteria that was modified by cationic polymer, thus creating antigen-loaded flagellate bacteria (denoted as 'FB-Ag') to overcome the skin barrier and perform the active delivery of antigen in the skin. The FB-Ag showed fast speed (∼0.2 μm s-1) and strong dendritic cell activation capabilities in the skin model in vitro. In vivo, the FB-Ag promoted the spread of antigen in the skin through active movement, increased the contact between Intradermal dendritic cells and antigen, and effectively activated the internal dendritic cells in the skin. In a mouse of pulmonary metastatic melanoma and in mice bearing subcutaneous melanoma tumor, the FB-Ag effectively increased antigen-specific therapeutic efficacy and produced long-lasting immune memory. More importantly, the FB-Ag also enhanced the level of COVID-19 specific antibodies in the serum and the number of memory B cells in the spleen of mice. The movement of antigen-loaded flagellate bacteria to overcome intradermal constraints may enhance the activation of intradermal dendritic cells, providing new ideas for developing intradermal vaccines.

Preclinical evaluation of performance, safety and usability of VAX-ID®, a novel intradermal injection device

The recent SARS-Cov2 pandemic and mpox health emergency have led to renewed interest in intradermal vaccination due to its dose sparing potential. Indeed, intradermal vaccination is particularly of interest for use in mass vaccination campaigns, pandemic preparedness programs, and/or for vaccines that are expensive or in short supply. Moreover, the rich immune network in the skin makes it an attractive target not only for prophylactic vaccination, but also for therapeutic vaccination, like immunotherapy and (dendritic) cell-based therapies. The aim of the current paper was to provide an overview of preclinical data generated with VAX-ID®, a novel intradermal drug delivery device, to allow assessing it performance, safety and usability. The device can overcome challenges seen with the Mantoux technique whereby the needle needs to be inserted under a shallow angle. Various parameters of VAX-ID® were evaluated, including dead-space volume, dose accuracy, penetration depth & liquid deposit in piglets, as well as usability by healthcare professionals. The device has shown to have a low dead volume and a high dose accuracy. Importantly, the device performed successful injections at a predefined depth into the dermis with a high safety profile as confirmed by visual and histological evaluation in piglets. Moreover, the device was rated as easy to use by healthcare professionals. The combined preclinical performance and usability findings indicate that VAX-ID® can provide reliable, standardized and accurate drug delivery in the dermal layer of the skin with a high ease of use. The device offers a solution for injection of various prophylactic as well as therapeutic vaccines.

Intraoperative Intradermal Application of Stromal Vascular Fraction into the Abdominal Suture Line: Histological Analysis of Abdominal Scar Tissue

BACKGROUND

Stem cell therapy is a promising new approach to wound healing. Stromal vascular fraction is a heterogeneous collection of cells, including adipose-derived stem cells, which are traditionally isolated using a manual collagenase-based technique. To our knowledge, this is the first human study that histologically assesses the potential of intraoperative intradermal injection of stromal vascular fraction on skin regeneration.

METHODS

In this controlled study, 20 patients undergoing deep inferior epigastric perforator flap breast reconstruction and bilateral flank liposuction were included. Stromal vascular fraction was injected intradermally into one side of the abdominal suture line, while the other side served as a control. Outcome measures included analysis of stromal vascular fraction by flow cytometry, histological analysis of scar tissue, and scar photography.

RESULTS

Cell yield for application and cell viability were 55.9 ± 28.5 × 10⁶ and 75.1% ± 14.5%, respectively. Age and body mass index were positively correlated with the number of cells for application and adipose-derived stem cells. Mean vascular density, elastic fiber content, collagen maturity (scar index), epidermal thickness, and number of rete ridges all showed higher values on the treated side. Furthermore, the injected number of adipose-derived stem cells and pericytes positively correlated with vascular density.

CONCLUSIONS

It is safe to speculate that intradermal stromal vascular fraction injection at the beginning of the healing process increases vascular density, collagen maturity and organization, elastic fiber content, epidermal thickness, epidermal-dermal anchoring of the scarring skin and is therefore responsible for improved skin regeneration. It is a viable and safe method that can be used as an adjunctive treatment in plastic surgery procedures where suboptimal wound healing is anticipated.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Microneedling Delivery of Botulinum Toxin Versus Intradermal Injection in the Treatment of Facial Hyperhidrosis

BACKGROUND

The current treatments of Facial hyperhidrosis (FH) are often limited and are associated with many adverse effects.

OBJECTIVE

The objective was to study the efficacy and safety of botulinum toxin-A delivery by microneedling versus its intradermal injection in the treatment of FH. Forty-two patients with FH were subjected to microneedling (Mn) followed by topical application of BTX-A on one side of the face and intra-dermal injection of BTX-A on the other side. Two sessions were performed at two week intervals. The assessment tools were Hyperhidrosis Disease Severity Scale (HDSS), the Dermatology Life Quality Index (DLQI), and patient satisfaction.

RESULTS

A score of one of HDSS was achieved in 85.7 percent of patients on the intradermally injected side versus 83.3 percent on the microneedling side (P=0.76%). Most of the patients on the injection side responded with the first session while the microneedling side responded with the second one (P<0.001). The DLQI was highly significant on both sides post-treatment (P<0.001). The side effects were mild in the form of pain on the intradermally injected sides, and mild transient erythema on the microneedling side. The microneedling side showed higher patient satisfaction compared to the intradermally injected side.

CONCLUSION

Both techniques were safe and effective in controlling the FH. Microneedling delivery of BTX-A was less painful and had higher patient satisfaction.

Performance and usability evaluation of novel intradermal injection device Immucise™ and reanalysis of intradermal administration trials of influenza vaccine for the elderly

Under the pandemic situation, there is an urgent need to produce and acquire sufficient quantities of prophylactic vaccines. It becomes important to devise a way to achieve reliable immunity with lower doses to distribute limited supplies of vaccines to maximum number of people very quickly. Intradermal (ID) vaccination is one such method to increase the effectiveness of vaccines. However, this method has not been widely used in general clinical practice because it is technically difficult to inject vaccines precisely into the ID tissue. Therefore, new ID delivery systems that allow reliable ID administration are under development. In this paper, we summarize its design and present the results of performance and usability testing for the Immucise™ Intradermal Injection System (Immucise™). This study showed that Immucise™ can reduce dead volume and inject drugs precisely into the ID tissues of subjects from infants to the elderly and can be used correctly and safely by healthcare professionals. This randomized controlled trial compared ID administration with Immucise™ and standard subcutaneous (SC) administration of seasonal influenza vaccine by analyzing the efficacy of the vaccine in the elderly group at 90 days and 180 days after administration. It was found that the vaccine for the ID group was as effective or more effective than that for the SC group up to 180 days later. It was also found that the geometric mean titer values, especially for B strains, were higher in the two-dose ID group than in the two-dose SC group. These findings suggest that Immucise™ is one of the best devices to distribute a small amount of vaccine quickly and widely to a larger number of people with little loss of vaccine during a pandemic.

Successful Treatment of Corticosteroid-Induced Rosacea-Like Dermatitis with Platelet-Rich Plasma Mesotherapy: Report of Seven Cases

INTRODUCTION

Corticosteroid-induced rosacea-like dermatitis (CIRD) is one of the cutaneous side effects of long and excessive application of topical corticosteroids, resembling rosacea that can present with a series of cutaneous manifestations. Most patients with CIRD undergo a variety of long-term treatments before their symptoms are relieved as there is no accepted standard therapy. We gave each of seven patients two sessions of platelet-rich plasma (PRP) mesotherapy before the routine treatment to restore their skin barrier function, and we were surprised to find that the patients' symptoms and appearance were significantly improved without any further treatments. Here we report this unexpected finding in dealing with CIRD.

CASE PRESENTATION

Seven patients, one male and six female, who had history of applying topical corticosteroids on the face for more than 3 months continuously or intermittently for various reasons were diagnosed with CIRD, showing varying degrees of erythema, telangiectasia, and papules, with dry skin, pain, and burning or stinging sensation. We intended to use the restorative effect of PRP to restore the skin barrier function of the patients for further treatment such as tacrolimus ointment, intense pulsed light (IPL), or pulsed dye laser (PDL), so they were treated twice with PRP intradermal injections using a mesogun injector machine. We used the VISIA skin detector to photograph and compare the changes after the treatments. Clinical efficacy was also assessed by the Global Aesthetic Improvement Scale (GAIS). Patients' assessments were recorded using three-point scale questionnaires. After two sessions of PRP treatment, before any further treatment, we were surprised to find that the patients' symptoms had improved significantly, as confirmed by VISIA skin detector and GAIS. All of the patients were satisfied with the outcomes, considering that mesotherapy was not painful and their appearance and symptoms had much improved.

CONCLUSIONS

PRP mesotherapy may mitigate sensitivity and inflammation in patients with CIRD by reducing erythema, telangiectasia, and papules. It is worth conducting large randomized controlled trials to verify its safety and efficacy in treating corticosteroid-induced rosacea-like dermatitis and maybe rosacea.

Fractional dose of intradermal compared to intramuscular and subcutaneous vaccination - A systematic review and meta-analysis

BACKGROUND

Vaccine supply shortages are of global concern. We hypothesise that intradermal (ID) immunisation as an alternative to standard routes might augment vaccine supply utilisation without loss of vaccine immunogenicity and efficacy.

METHODS

We conducted a systematic review and meta-analysis searching Medline, Embase and Web of Science databases. Studies were included if: licensed, currently available vaccines were used; fractional dose of ID was compared to IM or SC immunisation; primary immunisation schedules were evaluated; immunogenicity, safety data and/or cost were reported. We calculated risk differences (RD). Studies were included in meta-analysis if: a pre-defined immune correlate of protection was assessed; WHO-recommend schedules and antigen doses were used in the control group; the same schedule was applied to both ID and control groups (PROSPERO registration no. CRD42020151725).

RESULTS

The primary search yielded 5,873 articles, of which 156 articles were included; covering 12 vaccines. Non-inferiority of immunogenicity with 20-60% of antigen used with ID vaccines was demonstrated for influenza (H1N1: RD -0·01; 95% CI -0·02, 0·01; I² = 55%, H2N3: RD 0·00; 95% CI -0·01, 0·01; I² = 0%, B: RD -0·00; 95% CI -0·02, 0·01; I² = 72%), rabies (RD 0·00; 95% CI -0·02, 0·02; I² = 0%), and hepatitis B vaccines (RD -0·01; 95% CI -0·04, 0·02; I² = 20%). Clinical trials on the remaining vaccines yielded promising results, but are scarce.

CONCLUSIONS

There is potential for inoculum/antigen dose-reduction by using ID immunisation as compared to standard routes of administration for some vaccines (e.g. influenza, rabies). When suitable, vaccine trials should include an ID arm.

Intradermal Micro-Dosing of AbobotulinumtoxinA for Face-Lifting: How Long Does It Last?

INTRODUCTION

Intradermal injection of botulinum toxin type A (BoNT/A) has been used off-label by many clinicians for face-lifting. Previous studies on abobotulinumtoxinA (ABO) (Dysport®; Ipsen Biopharm Ltd.) have demonstrated clinical efficacy in face-lifting when compared to normal saline solution (NSS). However, few clinical studies have evaluated ABO in terms of duration of sustained effects for face-lifting.

METHODS

Thirty subjects were enrolled, and their face was injected with ABO at a dilution of 1 vial:7 mL (500 U in 7 mL of NSS) using an intradermal injection technique. Standardized photographic documentation was obtained using a two-, and three-dimensional imaging system (Vectra H1, Canfield Scientific, Inc, Fairfield, NJ) at baseline, immediately after injection, 2 weeks after injection and at 1 , 2 , 3 , 4 , 5 and 6 months of follow-up after treatment. The face-lifting effects were graded by both the subjects and two blinded dermatologists who compared photographs taken at the different time points. Side effects were also recorded at the end of the study.

RESULTS

Of the 30 subjects, 28 completed treatment and attended every follow-up visit. All subjects were female with Fitzpatrick skin type II to IV. The average age of the subjects was 27.6 ± 3.4 (range 22-34) years. The total number of ABO units used varied for each subject (range 200-250 U), with the average (± standard deviation) dose being 237 ± 19 units. Most of the subjects reported significant face-lifting up to 3 months post-procedure. However, face-lifting assessed by blinded dermatologists was notably lower than that of each patient's evaluation. The difference in the facial contouring volume of the nasolabial fold and jawline, as measured by the Vectra H1 imaging system, was statistically significant from baseline up until 3 months after injection (p = 0.001 and p = 0.001, respectively). The only side effect found in this study was minimal bruising, which was seen in 13.8% of subjects. None of the subjects reported facial asymmetry, either at rest or during facial expression.

CONCLUSION

The results of this study demonstrate the face-lifting effect of ABO intradermal injection. The results show sustained effects up to 3 months after injection.

Carboxyl-, sulfonyl-, and phosphate-terminal dendrimers as a nanoplatform with lymph node targeting

The development of drug delivery vehicles to cancer and/or immune cells in lymph nodes is important for cancer diagnosis, therapy, and immunotherapy. We previously reported that anionic carboxyl-terminal dendrimers were accumulated in lymph nodes. In this study, three anionic dendrimers with carboxyl-, sulfonyl-, and phosphate-terminal groups were prepared to examine the lymph node targeting and the association with immune cells in the lymph nodes. These anionic dendrimers were accumulated in the lymph node by intradermal injection. Although the carboxyl- and sulfonyl-terminal dendrimers were diffused from the injection site, the phosphate-terminal dendrimers were mostly retained. The phosphate-terminal dendrimer was recognized by the macrophages, dendritic cells, and B cells in the lymph node, whereas the carboxyl- and sulfonyl-terminal dendrimers were not. Our results show that these anionic dendrimers were accumulated in the lymph node where the association with immune cells could be controlled by the terminal structure of the dendrimer. The phosphate-terminal dendrimer can be used as a nanoplatform for the delivery of some bioactive molecules to some immune cells, including B cells, in the lymph node.

Long-term follow-up of intradermal injection of methylene blue for intractable, idiopathic pruritus ani

Background

While various medical treatments such as topical steroid ointment, antihistamine agent, and sedatives have been used for treating idiopathic intractable pruritus ani, they are not long-term solutions, due to the high recurrence rate. The aim of this study was to determine the effect of methylene-blue intradermal-injection therapy for treating patients with idiopathic intractable pruritus ani. Symptom improvement and recurrence rates were determined with a long-term follow-up.

Methods

A retrospective study was conducted from January 2011 to October 2013 on consecutive patients with intractable pruritus ani treated with methylene-blue intradermal injection. The therapy included 5 ml of 1% methylene blue and 15 ml of 1% lidocaine. Follow-up included a physical exam and satisfaction-score survey (1 = much worse, 2 = worse, 3 = no improvement, 4 = much better, 5 = gone completely) before treatment, 6 weeks after treatment, and 3 years after treatment to check patient status and recurrence rate.

Results

Of 103 treated patients, 96 were able to attend the 6-week follow-up visit. There were 58 (60.4%) males and 38 (39.6%) females with a mean age of 48.34 ± 10.21 years. Their mean satisfaction score at 6 weeks was 4.23 ± 0.86. Of the total of 96 patients, 9 (9.4%) patients scored 3 or less in their satisfactions score at 6 weeks. 62 (64.6%) patients were evaluated 3-year post-treatment. The satisfaction score at 3 years after treatment was 4.74 ± 0.57. Besides the 9 patients who initially failed treatment, 4 of the remaining 53 patients scored 3 or less in their satisfaction score surveys. Thus, the recurrence rate at 3 years was 7.5% (4/53).

Conclusions

Methylene-blue intradermal injection can result in a high symptom improvement rate with low recurrence rate for patients with idiopathic pruritus ani.

A Prospective Observational Study of the Effectiveness and Safety of Botulinum Toxin in the Horizontal Neck Lines

BACKGROUND

Botulinum toxin is used extensively, and its use for aesthetic indications in the lower face and neck is now becoming increasingly popular. It is the ideal alternative to surgical procedures for patients who are too young for facelift surgery or who are unwilling to take recuperation time. We review current approaches to BTX A treatment for horizontal neck lines.

METHODS

Subjects were 20 women with an average age of 43 with mild to moderate horizontal neck lines but have had no treatment by BTX A for the past 3 months. Injections are performed at points 1-1.5 cm apart along the horizontal lines with 1-2 U in each injection site, for a total of 15-30 U. Patients were followed up 3 and 8 days after treatment and then every 4 weeks after initial treatment for 16 weeks.

RESULTS

Except day 3 in the first neck line, the mean resulting from evaluation by the actual physician who performed the injection and two blinded physicians has statistical significance as shown by the maximum results at 8 weeks after injection. However, the patient improvement rate and satisfaction level did not exceed 50%. Adverse reactions were mild and transitory.

CONCLUSIONS

The overall results of applying BTX A are excellent, and the satisfaction level of treated patients is high to a certain extent. Moreover, smoothening of the neck skin was observed due to the intradermal effect. It is also a safe and effective therapeutic modality for any patient desiring rejuvenation of his or her neck, but who at the same time does not desire any recuperation time or is unwilling to undertake the potential risks associated with surgical procedures.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Comparative Study of UMA Jeunesse Classic® and UMA Jeunesse Ultra®

INTRODUCTION

The emergence of hyaluronic acid dermal fillers with lidocaine has transformed the minimally invasive treatment of wrinkles, lines and folds of the face. Patients can be treated quickly, painlessly and without the need for large doses of lidocaine. Therefore, it is important to scientifically evaluate the merits of lidocaine-containing products over those without.

METHODS

The two products, with (UJU) and without lidocaine (UJ), were randomly injected into nasolabial folds of 75 healthy volunteers with varying skin types in a split face study, age ranging 26-60 years. Only 73 subjects completed the follow-up. There were 68 females and 5 males with medium-to-deep nasolabial folds. All subjects were randomly injected with the two products on one or the other side of the face. Patients were followed up for 9 months.

RESULTS

Both products achieved significant improvement in the wrinkle severity score. Overall results were slightly better with UJU due to ease of injection, lack of pain and avoidance of topical or parenteral anaesthetic. In all other respects, differences in clinical data were not statistically significant. UJU^® was preferred by patients and injectors due to less pain during and after injection as compared to UJ^® (P < 0.0001). The overall rate of early and late complications with the two products was similar. Duration of maintenance of aesthetic effect between products also showed similarity. Optimum aesthetic effect was maintained in most cases for over 9 months with both products but patients in the 30-50-year age group did better. The patient acceptability rate was much higher with UJU.

CONCLUSION

Clinical data from this study suggest that performance and outcomes of treatment of medium-to-deep nasolabial folds with UJ and UJU are quite similar. However, treatment with UJU offers enhanced patient comfort and is preferred by patients and injectors.

LEVEL OF EVIDENCE I

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Safety, tolerability and efficacy of intradermal rabies immunization with DebioJect™

In a single-center study, 66 healthy volunteers aged between 18 and 50years were randomized to be immunized against rabies with three different injection routes: intradermal with DebioJect™ (IDJ), standard intradermal with classical needle (IDS), also called Mantoux method, and intramuscular with classical needle (IM). "Vaccin rabique Pasteur®" and saline solution (NaCl 0.9%) were administered at D0, D7 and D28. Antigen doses for both intradermal routes were 1/5 of the dose for IM. Tolerability, safety and induced immunogenicity of IDJ were compared to IDS and IM routes. Pain was evaluated at needle insertion and at product injection for all vaccination visits. Solicited Adverse Event (SolAE) and local reactogenicity symptoms including pain, redness and pruritus were recorded daily following each vaccination visit. Adverse events (AE) were recorded over the whole duration of the study. Humoral immune response was measured by assessing the rabies virus neutralizing antibody (VNA) titers using Rapid Fluorescent Focus Inhibition Test (RFFIT). Results demonstrated that the DebioJect™ is a safe, reliable and efficient device. Significant decreases of pain at needle insertion and at vaccine injection were reported with IDJ compared to IDS and IM. All local reactogenicity symptoms (pain, redness and pruritus) after injection with either vaccine or saline solution, were similar for IDJ and IDS, except that IDJ injection induced more redness 30min after saline solution. No systemic SolAE was deemed related to DebioJect™ and classical needles. No AE was deemed related to DebioJect™. No Serious Adverse Event (SAE) was reported during the study. At the end of the study all participants were considered immunized against rabies and no significant difference in humoral response was observed between the 3 studied routes.

Cost-effectiveness of an influenza vaccination program offering intramuscular and intradermal vaccines versus intramuscular vaccine alone for elderly

BACKGROUND

Intradermal (ID) injection is an alternative route for influenza vaccine administration in elderly with potential improvement of vaccine coverage. This study aimed to investigate the cost-effectiveness of an influenza vaccination program offering ID vaccine to elderly who had declined intramuscular (IM) vaccine from the perspective of Hong Kong public healthcare provider.

METHODS

A decision analytic model was used to simulate outcomes of two programs: IM vaccine alone (IM program), and IM or ID vaccine (IM/ID program) in a hypothetic cohort of elderly aged 65 years. Outcome measures included influenza-related direct medical cost, infection rate, mortality rate, quality-adjusted life years (QALYs) loss, and incremental cost per QALY saved (ICER). Model inputs were derived from literature. Sensitivity analyses evaluated the impact of uncertainty of model variables.

RESULTS

In base-case analysis, the IM/ID program was more costly (USD52.82 versus USD47.59 per individual to whom vaccine was offered) with lower influenza infection rate (8.71% versus 9.65%), mortality rate (0.021% versus 0.024%) and QALYs loss (0.00336 versus 0.00372) than the IM program. ICER of IM/ID program was USD14,528 per QALY saved. One-way sensitivity analysis found ICER of IM/ID program to exceed willingness-to-pay threshold (USD39,933) when probability of influenza infection in unvaccinated elderly decreased from 10.6% to 5.4%. In 10,000 Monte Carlo simulations of elderly populations of Hong Kong, the IM/ID program was the preferred option in 94.7% of time.

CONCLUSIONS

An influenza vaccination program offering ID vaccine to elderly who had declined IM vaccine appears to be a highly cost-effective option.

[A rare side effect of mesotherapy: Nicolau syndrome]

BACKGROUND

Nicolau's livedoid dermatitis is associated with drug-induced embolism in the cutaneous arterial bed, generally as a result of accidental intra-arterial injection. Herein, we report a case that is somewhat surprising because of its late onset following mesotherapy injections.

CASE REPORT

A 53-year-old man, with a history solely of tendinopathy for which he underwent mesotherapy sessions, consulted for livedoid lesions of the front of the knee with central necrosis. History-taking revealed a final course of mesotherapy three weeks earlier for patellar tendinitis below the left kneecap; intradermal injection of procaine and piroxicam had been unusually and intensely painful. The remainder of the clinical examination revealed additional livedoid lesions on the outside of the left ankle as well as purpuric lesions on the pads of the toes on the left foot. Laboratory tests revealed nothing of note. Skin biopsies of the livedoid circumference of the lesion showed arteriolar emboli of an amorphous material within the dermis obliterating the arteriolar lumen. The clinical appearance of skin lesions after mesotherapy led us to a diagnosis of Nicolau livedoid dermatitis.

DISCUSSION

Nicolau dermatitis is a rare skin complication described as occurring mainly as a result of intramuscular injections. The reported case is special because it comprises Nicolau dermatitis arising out of a session of mesotherapy employing an intradermal injection. However, there are only very few cases in which subcutaneous injections have induced Nicolau dermatitis. The pathophysiology is not well known, but several mechanisms are involved: arterial ischaemia by vasospasm or thrombosis. In this case, the semiotic appearance of the lesions and histological analysis militate in favour of accidental injection of a skin product into an arteriole, resulting in obliteration of the latter. Mesotherapy can induce Nicolau dermatitis.

Long-term CD4(+) and CD8(+) T-cell responses induced in HIV-uninfected volunteers following intradermal or intramuscular administration of an HIV-lipopeptide vaccine (ANRS VAC16)

BACKGROUND

We have shown that the intradermal (ID) administration of an HIV-1 lipopeptide candidate vaccine (LIPO-4) is well tolerated in healthy volunteers, with one fifth the IM dose delivered by this route inducing HIV-1-specific CD8(+) T-cell responses of a magnitude and quality similar to those achieved by IM administration. In this long-term follow-up, we aimed to investigate the sustainability and epitopic breadth of the immune responses induced.

METHODS

In a prospective multicentre trial, 68 healthy volunteers were randomised to receive, at weeks 0, 4 and 12, either a 0.5 ml IM (500 μg of each lipopeptide; 35 volunteers) dose or a 0.1 ml ID (100 μg of each lipopeptide; 33 volunteers) dose of the LIPO-4 vaccine, in the deltoid region of the non-dominant arm. All 68 volunteers received the first two vaccinations, and 44 volunteers in the ID group and 22 in the IM group received the third. We describe here the long-term CD8(+) and CD4(+) T-cell immune responses, up to 48 weeks after the first immunisation.

RESULTS

Response frequency was highest at week 14 for CD4(+) T cells, at 85% (28/33) for the IM group and 61% (20/33) for the ID group (p=0.027), and at week 48 for CD8(+) T cells, at 36% (12/33) for the ID group and 31% (11/35) for the IM group (p=0.67). Response rates tended to be lower for volunteers receiving the third vaccination boost, whether IM or ID. Finally, we also observed a striking change in the specificity of the CD8(+) T-cell responses induced shortly (2 weeks) or several months (48 weeks) after LIPO-4 vaccination.

CONCLUSION

Lipopeptide vaccines elicited sustainable CD4(+) and CD8(+) T-cell responses, following IM or ID administration. CD8(+) T-cell responses had shifted and expanded to different epitopes after one year of follow-up. These results should facilitate the design of the next generation of prime-boost trials with repeated doses of lipopeptide vaccines.