This R21 proposal under PA-10-069 offers to be a leap-forward in immunopharmacotherapy and NIDA's vaccine program for drugs of abuse and 'tests a novel and significant hypothesis which if confirmed by experiment would have a substantial impact on thinking regarding vaccines against small molecules'. The core platform exploits the newly discovered ability to chemically modify complement protein C3 in its native state with functional hydrazide molecules that was made in the PI's research. group to generate revolutionary vaccines based on small molecule drug of abuse molecules as immunogens complexed to C3. The four step theoretical approach to vaccine development is shown in Figure 1. The concept is at once simple, globally applicable and potentially ground breaking. The immunogen is a host protein (not foreign) and should not require an external adjuvant. The development and application of this new immunogen platform will be tested under the remit of the following two aims:
Aim 1 Design, synthesis and attachment of linear B-cell epitope-small molecules hydrazides to murine C3 (STEPS 1-3 of Figure 1). The aplication of this new immunopharmacotherapy platform primarily to cocaine (COC), and then to phencyclidine (PCP) and methamphetamine (MET) in mice will be investigated. Thus, mouse C3 (not human) will be isolated and purified for Step 1 of the process using a technique routine in the PI's lab. For Step 2, two hydrazide alkynes, incorporating the Mengo virus VP1259-277 linear B-cell epitope, will be synthesized in the PI's laboratory and these B-cell epitope hydrazide alkynes will be reacted with native murine C3 using conditions already developed in the PI's laboratory. For Step 3, azide analogs of cocaine, PCP and methamphetamine will be synthesized in the PI's laboratory and will be reacted with the C3-alkyne conjugates from Step 2 using standard 'click'chemistry conditions.
Aim 2. Active immunization of mice with C3-drug bioconjugates and quantification of the immune response (STEP 4 of Figure 1). The C3-bioconjugates from Aim 1 will be used to immunize female Balb/c mice (3-5 per group), in the presence and absence of external adjuvant (RIBIs). Anti-drug serum titers, polyclonal IgG binding affinity, binding specificity (drug versus B-cell epitope), and IgG persistence all being measured. Comparative immunizations with KLH-conjugates of the drugs will be performed as a control.
The ability to produce effective vaccines that allow immune system recognition of small molecules is a current unmet need in dug abuse sciences. This proposal harnesses the power of the innate immune system by chemical synthesis of small molecule vaccines coupled to complement protein C3 to generate novel small molecule vaccines.