A generalization of the Dirac equation to the case of affine symmetry, with SL(4, R) replacing SO(1, 3), is considered. A detailed analysis of a Dirac-type Poincaré-covariant equation for any spin j is carried out, and the related general interlocking scheme fulfilling all physical requirements is established. Embedding of the corresponding Lorentz fields into infinite-component SL(4, R) fermionic fields, the constraints on the SL(4, R) vector-operator generalizing Dirac's γ matrices, as well as the minimal coupling to (Metric-)Affine gravity are studied. Finally, a symmetry breaking scenario for SA(4, R) is presented which preserves the Poincaré symmetry.