An antisense oligonucleotide compound, composition, vaccine and methods for treating a variety of conditions characterized by up-regulation of IL-10 in a mammalian subject are disclosed. The compound (i) is composed of morpholino subunits and phosphorus-containing intersubunit linkages joining a morpholino nitrogen of one subunit to a 5′ exocyclic carbon of an adjacent subunit, (ii) is capable of uptake by monocytes, lymphocytes, and dendritic cells in a mammalian subject, (iii) contains between 10-40 nucleotide bases, and (iv) has a base sequence effective to hybridize to at least 12 contiguous bases of a target sequence contained in an exon-2 or exon-4 slice site region of human IL-10 pre-mRNA.