T- and B-Cell-Mediated Protection Induced by Novel, Live Attenuated Pertussis Vaccine in Mice. Cross Protection against Parapertussis

Despite the extensive use of efficacious vaccines, pertussis still ranks among the major causes of childhood mortality worldwide. Two types of pertussis vaccines are currently available, whole-cell, and the more recent acellular vaccines. Because of reduced reactogenicity and comparable efficacy acellular vaccines progressively replace whole-cell vaccines. However, both types require repeated administrations for optimal efficacy. We have recently developed a live attenuated vaccine candidate, named BPZE1, able to protect infant mice after a single nasal administration. infection. infection. However, in this case protection is only T cell mediated

Live Attenuated B. pertussis as a Single-Dose Nasal Vaccine against Whooping Cough

Pertussis is still among the principal causes of death worldwide, and its incidence is increasing even in countries with high vaccine coverage. Although all age groups are susceptible, it is most severe in infants too young to be protected by currently available vaccines. To induce strong protective immunity in neonates, we have developed BPZE1, a live attenuated Bordetella pertussis strain to be given as a single-dose nasal vaccine in early life. BPZE1 was developed by the genetic inactivation or removal of three major toxins. In mice, BPZE1 was highly attenuated, yet able to colonize the respiratory tract and to induce strong protective immunity after a single nasal administration. Protection against B. pertussis was comparable to that induced by two injections of acellular vaccine (aPV) in adult mice, but was significantly better than two administrations of aPV in infant mice. Moreover, BPZE1 protected against Bordetella parapertussis infection, whereas aPV did not. BPZE1 is thus an attractive vaccine candidate to protect against whooping cough by nasal, needle-free administration early in life, possibly at birth

Experimental Tuberculosis in the Wistar Rat: A Model for Protective Immunity and Control of Infection

BACKGROUND: Despite the availability of many animal models for tuberculosis (TB) research, there still exists a need for better understanding of the quiescent stage of disease observed in many humans. Here, we explored the use of the Wistar rat model for the study of protective immunity and control of Mycobacterium tuberculosis (Mtb) infection. METHODOLOGY/PRINCIPAL FINDINGS: The kinetics of bacillary growth, evaluated by the colony stimulating assay (CFU) and the extent of lung pathology in Mtb infected Wistar rats were dependent on the virulence of the strains and the size of the infecting inoculums. Bacillary growth control was associated with induction of T helper type 1 (Th1) activation, the magnitude of which was also Mtb strain and dose dependent. Histopathology analysis of the infected lungs demonstrated the formation of well organized granulomas comprising epithelioid cells, multinucleated giant cells and foamy macrophages surrounded by large numbers of lymphocytes. The late stage subclinical form of disease was reactivated by immunosuppression leading to increased lung CFU. CONCLUSION: The Wistar rat is a valuable model for better understanding host-pathogen interactions that result in control of Mtb infection and potentially establishment of latent TB. These properties together with the ease of manipulation, relatively low cost and well established use of rats in toxicology and pharmacokinetic analyses make the rat a good animal model for TB drug discovery

Experimental Comparative Study between Conventional and Green Parking Lots: Analysis of Subsurface Thermal Behavior under Warm and Dry Summer Conditions

Green infrastructure has a role to play in climate change adaptation strategies in cities. Alternative urban spaces should be designed considering new requirements in terms of urban microclimate and thermal comfort. Pervious pavements such as green parking lots can contribute to this goal through solar evaporative cooling. However, the cooling benefits of such systems remain under debate during dry and warm periods. The aim of this study was to compare experimentally the thermal behavior of different parking lot types (PLTs) with vegetated urban soil. Four parking lots were instrumented, with temperature probes buried at different depths. Underground temperatures were measured during summer 2019, and the hottest days of the period were analyzed. Results show that the less mineral used in the surface coating, the less it warms up. The temperature difference at the upper layer can reach 10 °C between mineral and non-mineral PLTs. PLTs can be grouped into three types: (i) high surface temperature during daytime and nighttime, important heat transfer toward the sublayers, and low time shift (asphalt system); (ii) high (resp. low) surface temperature during daytime (resp. nighttime), weak heat transfer toward the sublayers, and important time shift (paved stone system); and (iii) low surface temperature during daytime and nighttime, weak heat transfer toward the sublayers, and important time shift (vegetation and substrate system, wood chips system, vegetated urban soil). The results of this study underline that pervious pavements demonstrate thermal benefits under warm and dry summer conditions compared to conventional parking lot solutions. The results also indicate that the hygrothermal properties of urban materials are crucial for urban heat island mitigation

Protection by purified CD4⁺ T cells from BPZE1-immunized mice.

<p>Purified CD4⁺ or CD8⁺ T cells from BPZE1-immunized BALB/c mice (<b>a</b>) were transferred intraperitoneally to naïve SCID mice 24 h before they were intranasally infected with virulent <i>B. pertussis</i> BPSM. The mice were sacrificed 8 days later, and CFUs present in the lungs were counted (<b>b</b>). The results are expressed as means of log CFU values per lung from 5 mice per group (± standard error) and are representative of two independent experiments.</p

CD4⁺ T phenotype of IFN-γ-producing T cells following BPZE1 administration.

<p>BALB/c mice were left untreated (Naïve) or immunized intranasally with 10⁶ CFU of <i>B. pertussis</i> BPZE1 (BPZE1). Eight weeks later, the mice were sacrificed and spleens of three individual mice per group were pooled and homogenized to obtain single-cell suspensions. 2.5×10⁶ cells were cultured in triplicate overnight in the presence of 10 µg/ml PTX (PTX) or left unstimulated (Medium). Spleen-derived T cells were then labelled for surface expression of CD4 and CD8 (<b>a</b>), and intracellular IFN-γ expression by CD4⁺ (<b>b</b>) and CD8⁺ (<b>c</b>) T cells was assessed by flow cytometry. The results shown are representative of three independent experiments.</p

Transfer of protection by spleen cells and serum from BPZE1-immunized mice.

<p>100 µl of serum (<b>a</b>) or 50×10⁶ whole spleen cells (WSC) (<b>b</b>) or indicated amounts of WSC (<b>c</b>) from non-immunized (Naïve) or BPZE1-immunized (BPZE1) BALB/c mice were transferred intraperitoneally to SCID mice 24 h before they were intranasally infected with virulent <i>B. pertussis</i> BPSM (1×10⁶ CFU). Non-transferred SCID mice (No transfer) served as controls. The mice were sacrificed 7 days after challenge, and CFUs in the lungs were counted. The results are expressed as means of log CFU values per lung from 5 mice per group (± standard error) and are representative of three independent experiments.</p

IFN-γ and IL-17 are produced by distinct <i>B. pertussis</i>-specific CD4⁺ T cell subsets from BPZE1-immunized mice.

<p>BALB/c mice were left untreated (Naïve) or immunized intranasally with 10⁶ CFU of <i>B. pertussis</i> BPZE1 (BPZE1). Eight weeks later, the mice were sacrificed, and spleens of three individual mice per group were pooled and homogenized to obtain single-cell suspensions. 2.5×10⁶ cells were cultured in triplicate overnight in the presence (PTX) or absence (Medium) of 10 µg/ml PTX. Spleen-derived T cells were then labelled for surface expression of CD4, and intracellular IFN-γ and IL-17 expression was assessed by flow cytometry. The results are representative of three independent experiments.</p

Survival of <i>B. pertussis</i> and <i>B. parapertussis</i> in the presence of serum from non-immune or BPZE1-immunized mice.

<p>300 CFU of <i>B. pertussis</i> (<b>a</b>) and <i>B. parapertussis</i> (<b>b</b>) were incubated at 37°C for 1 h in the presence of 100 µl of 80% serum from unimmunized (Naïve) or BPZE1-immunized (BPZE1) mice and then plated onto Bordet Gengou blood agar plates for CFU counting. The results are presented as percent survival relative to that of a PBS control (in the absence of serum) (± standard error) for 3 mice per group, evaluated on 3 different plates per mouse, and are representative of three independent experiments.</p