NIAID-NOI-22-2115638 Statement of Work.pdf

STATEMENT OF WORK

Production of B Malayi Infective Larvae and Adult Worms

INTRODUCTION

The Laboratory of Parasitic Diseases (LPD) conducts basic and applied research on the prevention, control, and treatment of a variety of parasitic and bacterial diseases of global importance. The work of the group is largely directed toward the identification of immunological and molecular targets for disease intervention. The pathogens studied include parasitic protozoa (Leishmania, Toxoplasma, Giardia, Plasmodium, Trypanosoma cruzi, Cryptosporidium, Entamoeba) and helminths (Filariae, Schistosoma, Strongyloides, Taenia) as well as non-parasitic agents (e.g., mycobacteria). Much of this work is directed at uncovering basic aspects of the host-pathogen interaction in both humans and experimental animal models as well as in the invertebrate vectors that transmit medically important parasites.

BACKGROUND

Parasitic worms are required for ongoing studies of immunity of human to filariasis.

Lymphatic filariasis is one of the eight major diseases targeted as Neglected Tropical Diseases (NTD). To study the immune response to the parasite that causes lymphatatic filariasis as well as to develop an appropriate vaccine for the infection, large amounts of parasite materials are required for analysis and immunization experiments.

Brugia malayi is a filarial parasite which affects the lymphatic system and causes serious disease manifestations in humans, the most notable of which is elephantiasis. B.pahangi is very similar in many respects to B.malayi, and experimental infections of B.pahangi have been induced in man. Dogs and cats are susceptible to both species of filariae, but the expense of purchasing and maintaining large numbers of dogs and cats precludes the use of these animals unless it is specifically required. Some years ago, it was demonstrated that the Mongolian jird (Meriones unquiculatus) was highly susceptible to both B.pahangi and B.malayi, and infections established by conventional methods (i.e.

the subcutaneous inoculation of infective larvae) result in infection primarily of the lymphatic system. Having parasites in the lymphatics in jirds is of obvious advantage for certain studies; however, necropsy for recovery of developing larvae or adult worms from the lymphatics is tedious and time-consuming. Subsequent studies revealed that jirds inoculated intraperitoneally with infective larvae of either type parasite were not only quite useful for many types of experiments, but also served as a source of microfilarie, larvae and adult worms. In intraperitoneal infections, most of the worms in the peritoneal cavity are larger, and a higher percent recovery of worms was noted. Adult worms produced millions of microfilarie, most of which remained in the peritoneal cavity and can be collected by peritoneal lavage or at necropsy. Thus, intraperitoneal infections of B.pahangi and B.malayi provide a rich source of developing larvae, adult worms and microfilarie which are readily available.

To collect infective larvae, a membrane-feeding technique for infecting mosquitoes is used routinely. Use of this technique, allows for greater flexibility in choosing blood donors, results in more uniform infections in mosquitoes, and leads to higher yields of infective larvae. Thus, yields of infective larvae of these species can now be predicated with relative accuracy.

REQUIREMENTS:

Infective Larvae

Infective larvae of B.malayi will be produced in mosquitos (e.g. Aedes aegypti (Liverpool strain)) and collected by procedures used routinely in the laboratory. The larvae will be counted and treated as follows:

1) Stored at -80°C in a freezer until requested or the end of the contract period.

2) Injected intraperitoneally into jirds, or suspended in media 199 and shipped immediately to LPD by air express.

3) Sixty to ninety days later, adult worms will be collected from the peritoneal cavity of jirds and stored at -80°C until needed or suspended in media and shipped immediately by air express.

B.malayi shall be routinely maintained in cats and mosquitoes. Four to five day old adult mosquitoes shall be membrane fed on infected cat blood containing approximately 200 mf/20 cmm. Fourteen days later, the infective larvae shall be harvested by anesthetizing the mosquitoes, crushing them gently in a mortar containing HBSS, and placing this material in a basket made of 100 mesh wire, which shall be placed into a petri dish containing HBSS.

Inoculation of cats and jirds

Approximately 200 larvae shall be injected subcutaneously into each cat. Microfilariae are not present in the peripheral blood until 90 to 120 days post-inoculation. Jirds shall be given 400 larvae by intraperitoneal inoculation for the establishment of infection with developing larvae, adult worms, or microfilarie in the peritoneal cavity.

DELIVERABLES:

One hundred-ten thousand (110,000) infective larvae (or larval equivalents including adults) shall be produced per year. Approximately one-half of these shall be frozen and provided to LPD upon request and the remaining shall be inoculated intraperitoneally into jirds.

GOVERNMENT FURNISHED

There will be no Government furnished supplies or materials.

OPTIONS

In addition to the services/quantities outlines above to be provided for the base requirement, Option(s) for additional services/ quantities under the contract may be exercised at the discretion of the Government and are defined as follows:

Option Year 1 – 5: Extend the Period of Performance: The Government includes options to extend the period of performance. Each option is for one additional year of performance. The total period of performance resulting from the base period of 6 months plus all potential Term options is five (5) years. If Option periods are exercised, the services required will be the same as provided during the 6-Month base.

Optional Quantities may be exercised under each option period to extend the period of performance and need to be definitized. Option 1 Period, Optional Quantity 1: up to 20,000 additional infective larvae. Option 1 Period, Optional Quantity 2: up to 40,000 additional infective larvae. Option 1 Period, Optional Quantity 3: up to 60,000 additional infective larvae.

There can be multiple Optional Quantities under an Option Period to extend the period performance. Should the number of additional supplies or service exceed the negotiated Option Quantities for each Option Period (to extend the period of performance), a change order will be issued as long as the supply or service is within scope of the Statement of Work.

REPORTING REQUIREMENTS

a. Technical Reports

The contractor will be required to submit quarterly reports within 30 calendar days of the reporting period, on the number of parasites sent (and/or cryopreserved).

PERIOD OF PERFORMANCE

The period of performance for full performance will be five (5) years that includes a base and if exercised four (4) 1-year options and one (1) 6-month option with option periods.

Inoculation of cats and jirds